Instructions to Authors

Overview
Standards for Reporting Scientific Data
Tools for Diagnostic Accuracy
Journal Policies
Types of Submissions
Manuscript Preparation
Online Submission and Tracking
Post-Acceptance
Clinical Chemistry Editorial Office

Overview

Clinical Chemistry, issued monthly, is published in print and electronically by the American Association for Clinical Chemistry (AACC) in partnership with Oxford University Press. The journal welcomes contributions, either experimental or theoretical, in the field of laboratory medicine. It is the leading forum for peer-reviewed, original research on innovative practices in today’s clinical laboratory. In addition to being the most cited journal in the field, Clinical Chemistry has the highest Impact Factor among journals of clinical chemistry, clinical (or anatomic) pathology, analytical chemistry, and the subspecialties, such as transfusion medicine and clinical microbiology.

Submissions of the following nature are welcomed:

Basic materials or principles
Analytical techniques
Molecular diagnostics
Test utilization or testing-related health or financial outcomes
Instrumentation
Data processing
Statistical analyses of data
Clinical investigations in which laboratory testing has played a major role
Laboratory animal studies of chemically oriented problems of human disease

Contributions should consist of subject matter that is original and significantly advances the state of knowledge of clinical chemistry, and conclusions that are justified from the design of the experiments and the data presented. The information must be sufficiently detailed to permit replication of the work by a competent worker in the field. Lastly, the writing must be clear, concise, and grammatically correct.

Equal consideration is given to original manuscripts in English from any country, regardless of membership in the Association. It is, however, advised that all non-English speaking authors enlist the aid of a native-English speaking colleague to correct English language usage before submission. Submissions must adhere to the current International Committee of Medical Journal Editors (ICMJE) Recommendations for the Conduct, Reporting, Editing, and Publication of Scholarly Work in Medical Journals.

All Clinical Chemistry submissions, correspondence, and reviews must be in English. Manuscript content and writing responsibility remains with the author; however, several professional writing/editing services are available to assist authors. Clinical Chemistry does not endorse any editing service nor is Clinical Chemistry responsible for any services performed. These include but are not limited to:

www.bioedit.co.uk
www.bioscienceeditingsolutions.com
www.biosciencewriters.com
www.bluepencilscience.com
www.bostonbioedit.com
www.charlesworthauthorservices.com
www.editage.com
www.enago.com
www.journalexperts.com
www.prof-editing.com
www.sciencedocs.com
www.stallardediting.com
www.hzlxsw.com

Contributions may be submitted via the manuscript tracking system. Please contact the Editorial Office via e-mail (clinchemed@aacc.org) should you have any questions or need assistance. Please also visit https://academic.oup.com/journals/pages/authors for information about publishing in an Oxford Academic journal.

Standards for Reporting Scientific Data

Description of Analytical Methods and Results
Statistics
Studies with Human Subjects
Animal Studies
NIH Funding/Open Access Requirements
Checklist for the Description of Sequence Variants at the Human Genome Variation Society

Description of Analytical Methods and Results

Manuscripts describing the development and evaluation of the performance of methods and instruments should discuss linearity, imprecision, analytical specificity, recovery, lower limit of detection, comparability with other analytical methods, lower limit of quantification and reference interval(s). Some clinical data are usually needed.

Document the analytical advantages of the new or modified method over existing methods.

Analytical method validations should conform to the protocols and requirements in the Center for Drug Evaluation and Research (CDER) Guidance for Industry: Bioanalytical Method Evaluation, 2001 (1).

Calibration curves and linearity: Data for these studies should be analyzed by linear regression analysis (if a linear response is obtained) and should include the slope, intercept, r2, standard deviation of residuals, and the standard deviations of the slope and intercept.

Standard deviations of repeated points may be included.

In preparing nonlinear calibration curves, authors may use any objective, statistically valid method but must specify the method used (see, e.g., (2)).

Imprecision: Studies must include estimates of "within-run" and "total" standard deviations (2). Each should be determined at low, normal, and above-normal concentrations with use of specimens that are in an appropriate biological matrix.

One method for estimating both within-run and total standard deviations is the analysis of variance experiment described in NCCLS EP5-T (3), which calls for two replicates per specimen per run and two runs per day for 20 days. This permits separate estimation of between-day and between-run, within-day standard deviations, as well as within-run and total standard deviations.

For acceptable alternatives that include only one run per day, see the cited document.

Indicators of Accuracy ("Trueness"): Accuracy (or “trueness” in the recent nomenclature) of a new method can be estimated by (a) analyses of certified Reference Materials by the new method or (b) comparisons of results of a new method with results of a Reference Method. These are the only accepted approaches to trueness. When neither is available, other evidence relevant to the ability of the method to measure the analyte (measurand) is needed. Recovery studies involve analyses after known amounts of analyte are added to the biological fluid on which the determination will be performed. Recovery of added analyte should be calculated [(final concentration – initial concentration)/added concentration], not the observed final concentration as a proportion of expected final concentration.

Interference studies should be performed to assess the effects of common interferents, including lipid particles, hemoglobin, bilirubin, and components of uremic plasma. Exogenous materials, such as ingredients of blood collection containers (tubes) and commonly used or commonly coadministered drugs that might interfere with the determination, should also be tested for interferences. Selection of materials to test should be guided by an understanding of the chemistry and physics of the measuring system. Thus chemicals that are structurally similar to the analyte should be tested to assess the selectivity of the method. (The term “selectivity” is preferred over specificity; selectivity can be quantified.) In characterizing non-spectrophotometric methods, chemicals that may interfere in the detection system should be studied more intensively than chemicals that are historically important for interference in spectrophotometric methods.

Comparison-of-methods studies should compare results by the new or proposed method with those by a reference-quality method or other generally accepted analytical method for which assay performance is documented (4, 5).

It is desirable to test 100 to 200 different samples from patients who have been selected to include a wide variety of pathologic conditions and to present a range of values for the analyte that includes those likely to be encountered in routine application.

For a table of the required number of samples, see Linnet (6).

If regression analysis is used for statistical evaluation of the data, supply slopes and intercepts (and their standard deviations) and standard deviations of residuals (Sy|x, often called standard errors of estimates). Unbiased (e.g., Deming) regression is typically required (7). A program to perform Deming regression is available online as a supplement from this journal (8).

The correlation coefficient has limited utility. Residuals plots [e.g., Bland-Altman (9, 10)] are often useful. On the horizontal axis, plot the mean of results by the two studied methods, not the result of one method.

Analytical sensitivity and detection limit: These terms are commonly confused. The International Union of Pure and Applied Chemistry defines analytical sensitivity as the ability of an analytical procedure to produce a change in signal for a defined change of the quantity. This is often visualized as the slope of the calibration curve.

The limit of detection (LOD) is defined as the lowest concentration or amount of an analyte that can be reliably identified as being qualitatively present in the sample. The limit of quantification (LOQ) is defined as the lowest concentration or amount of analyte that can be reproducibly quantified in a sample. The most acceptable criteria for ascertaining the LOQ is the concentration of analyte that can be measured with an imprecision of less than 20% and a deviation from target of greater or less than 20% (1). The operational definition of the LOD and LOQ must be supplied by the author. Additional considerations related to this topic are presented by Linnet (11).

Analytical quality: Results obtained for the performance characteristics should be compared objectively with well-documented quality specifications, e.g., published data on the state-of-the-art performance required by regulatory bodies such as CLIA 88, or recommendations documented by expert professional groups (12).

Reference interval (normal range): Depending on the conclusions of the accuracy studies, modification of an accepted reference interval may be indicated. Description of the reference interval study should include details about sampling; selection of subjects, including their number, age, and sex distribution; the statistical method for summarizing the results (13); and other factors that would influence the values obtained.

Mass spectrometric assays must be evaluated for matrix effects (ion suppression or enhancement) (14, 15).

Chromatograms: Chromatograms from gas-liquid and liquid chromatography should usually be presented so that readers can see the efficiency of the separation and observe the resolution from interferents in the matrix. Similar images are often needed for electrophoretic separations.

Enzyme activities: Enzyme activities may be expressed in international units (U) or katals. Temperature and other key assay features must be described in the text or by reference to a published method.

When first mentioned in the text, enzymes (whether measured by activity or mass assays) must be numbered (EC no.) in accordance with the recommendations of the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology on the Nomenclature and Classification of Enzymes (16).

References:

1. Center for Drug Evaluation and Research (CDER) Guidance for Industry: Bioanalytical Method Evaluation, 2001.
2. Linnet K, Boyd JC. Selection and analytical evaluation of methods – with statistical techniques. In: Burtis CA, Ashwood ER, Bruns DE. Tietz textbook of clinical chemistry and molecular diagnostics. 4th ed. St. Louis: Saunders, 2006: 353-407.
3. NCCLS Tentative Guideline EP5-T. User evaluation of precision performance of clinical chemistry devices. Wayne, PA: National Committee for Clinical Laboratory Standards, June 1984.
4. Carey RN, Garber CC. Evaluation of methods. In: Kaplan LA, Pesce AJ, eds. Clinical chemistry. Theory, practice and correlation, 2nd ed. St. Louis: CV Mosby, 1989:290–310.
5. Koch DO, Peters T Jr. Selection and evaluation of methods. In: Burtis CA, Ashwood ER, eds. Tietz textbook of clinical chemistry, 2nd ed. Philadelphia: WB Saunders, 1994:508–25.
6. Linnet K. Necessary sample size for method comparison studies based on regression analysis. Clin Chem 1999;45:882–94.
7. Linnet K. Evaluation of regression procedures for methods comparison studies. Clin Chem 1993;39:424–32. 
8. Martin RF. General Deming regression for estimating systematic bias and its confidence interval in method-comparison studies. Data supplement. GDR: Executable program for general Deming regression calculations and graphics. 
9. Bland JM, Altman DG. Statistical methods for assessing agreement between two methods of clinical measurement. Lancet 1986;1:307–10.
10. Altman DG, Bland JM. Commentary on quantifying agreement between two methods of measurement. Clin Chem 2002;48:801-2.
11. Linnet K, Kondratovich M. Partly nonparametric approach for determining the limit of detection. Clin Chem 2004;50:732-40. 
12. Fraser CG, Petersen PH. Analytical performance characteristics should be judged against objective quality specifications. Clin Chem 1999;45:321–3. 
13. Solberg HE. Establishment and use of reference values. In: Burtis CA, Ashwood ER, eds. Tietz textbook of clinical chemistry, 4th ed. St. Louis: Saunders, 2006:425–48.
14. Annesley TM. Ion Suppression in Mass Spectrometry. Clin Chem 2003;49:1041-44. 
15. Matuszewski BK, Constanzer ML, Chavez-Eng CM. Strategies for the assessment of matrix effect in quantitative bioanalytical methods based on HPLC-MS.MS. Anal Chem 2003;75:3019-30. 
16. International Union of Biochemistry and Molecular Biology, Nomenclature Committee. Enzyme nomenclature 1992. San Diego: Academic Press, 1992:862pp.

Statistics 

Describe statistical methods with enough detail to enable a knowledgeable reader with access to the original data to verify the reported results.

When possible, quantify findings and present them with appropriate indicators of measurement error or uncertainty.

Avoid sole reliance on statistical hypothesis testing, such as the use of P values, which fails to convey important quantitative information.

When appropriate, confidence intervals should be presented; see, e.g., Harris (1), Henderson (2), and references therein.

References:

1. Harris EK. On P values and confidence intervals (why can't we P with more confidence?) [Editorial]. Clin Chem 1993;39:927-8.
2. Henderson AR. Chemistry with confidence: should Clinical Chemistry require confidence intervals for analytical and other data? [Opinion]. Clin Chem 1993;39:929-35.

Studies with Human Subjects

Clinical Chemistry's policy regarding studies with human subjects adheres to the recommendations from the International Committee of Medical Journal Editors (ICMJE). All investigators should ensure that the planning, conduct, and reporting of human research are in accordance with the Helsinki Declaration as revised in 2013. All authors should seek approval to conduct research from an independent local, regional, or national review body (e.g., ethics committee, institutional review board). If doubt exists whether the research was conducted in accordance with the Helsinki Declaration, the authors must explain the rationale for their approach and demonstrate that the local, regional, or national review body explicitly approved the doubtful aspects of the study. Approval by a responsible review body does not preclude editors from forming their own judgment whether the conduct of the research was appropriate.

Patients have a right to privacy that should not be violated without informed consent. Identifying information, including names, initials, or hospital numbers, will not be published in written descriptions, photographs, or pedigrees unless the information is essential for scientific purposes and the patient (or parent or guardian) gives written informed consent for publication. Informed consent for this purpose requires that an identifiable patient be shown the manuscript to be published. Authors should disclose to these patients whether any potential identifiable material might be available via the Internet as well as in print after publication. Authors should obtain and archive written patient consent forms in accordance with local regulations or laws and will be required to attest in writing upon submission that they have received and archived written patient consent.

Nonessential identifying details should be omitted. Informed consent should be obtained if there is any doubt that anonymity can be maintained. For example, masking the eye region in photographs of patients is inadequate protection of anonymity. If identifying characteristics are de-identified, authors should provide assurance, and editors should so note, that such changes do not distort scientific meaning. When informed consent has been obtained, this will be indicated in the published article. Please note if informed consent has been received in the Materials and Methods section of the submitted manuscript.

Animal Studies

Clinical Chemistry's policy regarding studies reporting experiments on animals adheres to the recommendations from the International Committee of Medical Journal Editors (ICMJE). When reporting experiments on animals, authors should indicate whether institutional and national standards for the care and use of laboratory animals were followed. Further guidance on animal research ethics is available from the International Association of Veterinary Editors’ Consensus Author Guidelines on Animal Ethics and Welfare.

NIH Funding/Open Access Requirements

The National Institutes of Health (NIH) has implemented its "Policy on Enhancing Public Access to Archived Publications Resulting from NIH Funded Research." This policy requests that authors reporting research that is funded (in whole or part) by a current NIH grant submit to NIH PubMed Central (PMC) manuscripts after they have been peer reviewed and accepted for publication in scientific journals. The “accepted manuscript” is the version of the manuscript after the author’s final revision but before post-acceptance editing and copyediting. The Policy is available online. The policy applies to manuscripts accepted for publication in Clinical Chemistry on or after May 2, 2005.

The policy requests that the release date to the public be within 12 months after the official date of final publication. Clinical Chemistry’s existing policy that has been in effect since the Journal first appeared online in 1998 is to make all content publicly available 12 months after publication date. Authors have the option to request that their papers be made open access at the time of online publication, for a fee. Authors will receive instructions on how to select an open access license after acceptance. For more information, visit https://academic.oup.com/journals/pages/open_access.

All papers published under an open access license will be automatically deposited to PubMed Central. Any paper funded by the NIH should have NIH clearly listed as a funder, and those papers will be automatically deposited to PubMed Central with a 12-month embargo.

Checklist for the Description of Sequence Variants at the Human Genome Variation Society

Requirements for the description of sequence variants can be found at online. 

Tools for Diagnostic Accuracy

Studies of Diagnostic Accuracy (STARD)
Outcomes Studies (CONSORT)
Minimum Information about a Microarray Experiment (MIAME)
Minimum Information about Quantitative Real-Time PCR Experiments (MIQE)

Studies of Diagnostic Accuracy (STARD)

STARD 2015 Statement

The Standards for Reporting Diagnostic Accuracy Studies (STARD) statement first appeared in 2003 (1, 2) and was updated in 2015 (3).

For studies of diagnostic accuracy of tests, complete the STARD Checklist for Evaluations of Diagnostic Accuracy (3) electronically upon submission. Do not send the checklist via e-mail or upload it as supplemental material.

The STARD statement (3) provides guidance helping authors to modify their manuscript as needed to provide the requested information. Guidelines include:

• Provide literature reference(s) describing the evaluated test(s) and criterion "gold standard" test(s) or include detailed descriptions of them.
• Follow accepted methodologic standards including the following:
  • Specify spectrum of evaluated patients (age and sex distributions, eligibility criteria, and summary of symptoms or disease stage).
  • Analyze pertinent subgroups of subjects (e.g., symptomatic and asymptomatic patients).
  • Avoid verification bias (usually by application of a "gold-standard" test to all subjects rather than to a clinically selected subset).
  • Categorize test results and patients independently to avoid reviewer bias (usually by performance of tests with blinding to patient information and vice versa).
  • Provide confidence intervals (or SE) for indices of diagnostic accuracy such as sensitivity/specificity, likelihood ratios, and areas under receiver-operating characteristic (ROC) curves (4).
  • Indicate the number of indeterminate test results and their use (if any) in further data analysis.
  • Provide laboratory data on analytical imprecision of the test (usually day-to-day CV at two or more concentrations) or reproducibility of observer interpretation (e.g., for a visually read, dichotomous [positive/negative] test).
  • A flow diagram is strongly recommended (3).

When evaluating diagnostic accuracy in clinical studies, simple testing of the significance of differences between mean values of patient groups (e.g., by Student’s t-test) provides insufficient information to assess diagnostic accuracy.

Scatter plots of data, calculations of diagnostic sensitivities and specificities and their confidence intervals (4), and use of approaches such as ROC curves (5), cumulative distribution analyses (6), likelihood ratios (7), and discriminant analysis (8) provide information that is appropriate to specific situations.

Confidence intervals should be provided (3).

Discussions of predictive values in illustrative settings may be useful additions to assess the potential clinical utility of tests.

Analysis of serial measurements requires special attention (9).

References:

1. STARD Group. Towards complete and accurate reporting of studies of diagnostic accuracy: the STARD statement. Clin Chem 2003;49:1-6. 
2. Bossuyt PM, Reitsma JB, Bruns DE, Gatsonis CA, Glasziou PP, Irwig LM, et al. The STARD statement for reporting studies of diagnostic accuracy: explanation and elaboration. Clin Chem 2003;49:7-18. 
3. Bossuyt PM, Reitsma JB, Bruns DE, Gatsonis CA, Glasziou PP, Irwig LM, et al. STARD 2015: An updated list of essential items for reporting diagnostic accuracy studies. Clin Chem 2015;61:1446–52. 
4. Harper R, Reeves B. Reporting of precision of estimates for diagnostic accuracy: a review. BMJ 1999;318:1322-3.
5. Zweig MH, Campbell G. Receiver-operating characteristic (ROC) plots: a fundamental evaluation tool in clinical medicine [Review]. Note that in Figs. 4-12 in this paper, the labels for the x-axis at the top and bottom are reversed. The (correct) dual labeling of the x-axis solves the problem of whether to plot specificity or 1 - specificity on the x-axis. Clin Chem 1993;39:561-77. 
6. Krouwer JS. Cumulative distribution analysis graphs-an alternative to ROC curves [Technical Brief]. Clin Chem 1987;33:2305-6.
7. Albert A. On the use and computation of likelihood ratios in Clinical Chemistry. Clin Chem 1982;28:1113-9. 
8. Solberg HE. Discriminant analysis. Crit Rev Clin Lab Sci 1978;9:209-42.
9. Matthews JNS, Altman DG, Campbell MJ, Royston P. Analysis of serial measurements in medical research. Br Med J 1990;300:230-5.

Outcomes Studies (CONSORT)

Outcomes studies (CONSORT)

The CONSORT statement (1), although designed for randomized controlled trials and used for therapeutic rather than diagnostic interventions, is recommended as an often-useful guide.

For questions, contact Clinical Chemistry via e-mail (clinchemed@aacc.org).

References:

1. Moher D, Schulz KF, Altman DG for the CONSORT Group. The CONSORT statement: revised recommendations for improving the quality of reports of parallel group randomized trials. www.consort-statement.org.

Minimum Information About a Microarray Experiment (MIAME)

The MIAME Checklist can be found online.

MIAME describes the minimum information about a microarray experiment that is needed to enable interpretation of the results of the experiment unambiguously and potentially to reproduce the experiment.

The MIAME checklist is a description of MIAME principles designed to help authors, reviewers, and editors of scientific journals meet MIAME requirements and to make microarray data available to the community in a useful way.

MIAME is neither a dogma nor a legal document - it assumes a cooperative data provider and a fair reviewer.

Minimum Information About Quantitative Real-Time PCR Experiments (MIQE)

MIQE Checklist

For studies that include quantitative real-time PCR experiments, complete the MIQE checklist for evaluation of qPCR experiments during electronic submission. Do not send the checklist via e-mail or upload it as supplemental material. The full text of the MIQE guidelines is available online. A PDF version for all essential components of the checklist can be obtained by the link above.

Recommended nomenclature should be used, including:

qPCR for quantitative real-time PCR
RT-qPCR for reverse transcription quantitative real-time PCR
reference genes instead of housekeeping genes
hydrolysis probes instead of TaqMan® probes
dual hybridization probes for HybProbes® (LightCycler®) probes
quantification instead of quantitation
Cq instead of Ct, Cp, or TOP
quantification cycle instead of threshold cycle or crossing point

Authors are also encouraged, but not required, to include the additional desirable items of the MIQE guidelines (1). The MIQE guidelines are intended to help authors plan, perform and present qPCR experiments. They are also a guide for reviewers and editors to judge the quality of qPCR data. Incomplete information may be grounds for manuscript rejection. Use of Supplemental Data is encouraged as necessary. The most common errors in performing and reporting qPCR data include:

Not enough information for others to replicate the experiment, including how the nucleic acid was prepared, reverse transcribed, and amplified. Primer sequences are required. Probe sequences are strongly encouraged especially in methods manuscripts, but their omission may be acceptable in clinical manuscripts if they are commercially available as products.

Inadequate storage and/or nucleic acid preparation, leading to poor nucleic acid quality and variable results.

Suboptimal primers for reverse transcription and/or PCR resulting in low yield, specificity and/or PCR efficiency.

Inappropriate analysis of data.

Use of a single reference gene in RT-qPCR without justification (2).

The guidelines require not only delineation of what was done, but presentation of evidence that validates the method used. For example, these include evidence of RNA integrity and purity, PCR specificity, calibration curves and calculations of PCR efficiency and limits of detection. At the option of the editor, MIQE requirements may be relaxed in reports using qPCR arrays, although all manuscripts will be judged on their relative merit, and the relative merit of a manuscript using qPCR increases as compliance with the MIQE guidelines increases.

References:

1. Bustin SA, Benes V, Garson JA, Hellemans J, Huggett J, Kubista M, Mueller R, Nolan T, Pfaffl MW, Shipley GL, Vandesompele J, Wittwer CT. The MIQE guidelines: minimum information for publication of quantitative real-time PCR experiments. Clin Chem. 2009 Apr;55(4):611-22.
2. Vandesompele J, De Preter K, Pattyn F, Poppe B, Van Roy N, De Paepe A, Speleman F. Accurate normalization of real-time quantitative RT-PCR data by geometric averaging of multiple internal control genes. Genome Biol. 2002 Jun 18;3(7):RESEARCH0034.

Journal Policies

Originality
Data and Preprints

Originality

Clinical Chemistry adheres to the recommendations from the International Committee of Medical Journal Editors (ICMJE) and the Committee on Publication Ethics (COPE) for guidance on policies and procedures regarding overlapping publications. Misconduct including, but not limited to, the following is strictly prohibited and will result in immediate removal of a paper from consideration by the journal.

Duplicate Submissions
Submissions that are under review or that have been previously published with another journal.

Duplicate Publications and Plagiarism
Manuscripts that have substantial overlap with a manuscript that has already been published, without proper citation.

Availability of Data and Materials

Where ethically feasible, Clinical Chemistry strongly encourages authors to make all data and software code on which the conclusions of the paper rely available to readers. We suggest that data be presented in the main manuscript or additional supporting files—or deposited in a public repository whenever possible. For information on general repositories for all data types, and a list of recommended repositories by subject area, please see  Choosing where to archive your data.

Data Citation

Clinical Chemistry supports the Force 11 Data Citation Principles and requires that all publicly available datasets be fully referenced in the reference list with an accession number or unique identifier such as a digital object identifier (DOI). Data citations should include the minimum information recommended by DataCite:

• [dataset]* Authors, Year, Title, Publisher (repository or archive name), Identifier

*The inclusion of the [dataset] tag at the beginning of the citation helps us to correctly identify and tag the citation. This tag will be removed from the citation published in the reference list.

Preprint policy

Authors retain the right to make an Author’s Original Version (preprint) available through various channels, and this does not prevent submission to the journal. For further information see our Online Licensing, Copyright and Permissions policies. If accepted, the authors are required to update the status of any preprint, including your published paper’s DOI, as described on our Author Self-Archiving policy page.

Clinical Chemistry will consider submitted papers that have had a previous version posted on a noncommercial preprint server on a case-by-case basis. In examining submissions with an existing preprint, the editors will consider such factors as whether the submitted manuscript will add meaningful new information to the literature. Authors must declare at first submission that their paper is available as a preprint and must provide the name of the preprint server, the DOI, and a link to the preprint. This information should be included in the cover letter to the editor as well as in the designated field in the submission system. If the authors fail to declare the existence of a preprint at initial submission, this may be cause for rejection.

Editors will not look favorably on work generated by a particular methodology that has only been listed or referenced in the preprint and has not gone through the peer-review process. A manuscript may not be posted to a preprint server once it has already been submitted and is under consideration by the journal.

Authors must retain their copyright to the preprint and will be required to transfer copyright to the journal if the manuscript is accepted. The preprint itself cannot be indexed in PubMed or MEDLINE.

Preprints may be cited in the references section; however, the editors will determine their suitability on a case-by-case basis. References to non-peer-reviewed, methods-based papers are not permitted. References to preprints should follow this format: 

Mao Q, Chin R, Xie W, Deng Y, Xu H, Zhang RY, et al. Advanced whole genome sequencing and analysis of fetal genomes from amniotic fluid. Preprint at https://www.biorxiv.org/content/early/2017/08/08/173807 (2017). 

See editorial published in the July 2018 issue for more about the journal’s philosophy on preprints.

Types of Submissions

Article
Citation Classic
Clinical Case Study/Commentary
Clinical Chemist
Clinical Toxicology Series
Correction
Editorial
Genetic Metabolic Series
Inspiring Minds
Letter to the Editor/Reply
Looking to the Past
Mini-Review
News & Views
Opinion
Perspective
Point/Counterpoint
Q&A
Reflection
Review
Special Report
Unveiling the Right Side
What Is Your Guess?

Article

Research or scientific articles are submitted directly from authors. There are no restrictions on topics that are considered for publication, as long as the subject matter is original and relates experimentally or theoretically to the field of laboratory medicine. The information must be sufficiently detailed not only to enable readers to understand and appreciate the material presented, but also to permit replication of the work by other scientists in the field.

Articles should contain a structured abstract limited to 250 words and formatted to include separate headings of: Background, Methods, Results, and Conclusions. The main text should not exceed 3,500 words. The manuscript should have no more than 40 references and a total of 6 tables and/or figures. Supplemental data are permitted for Articles.

Articles should list no more than 20 authors, with any additional contributors listed in the Acknowledgments. Although exceptions are rare, you may email clinchemed@aacc.org detailing each author's contribution to your submission, which will be forwarded to the editor.

Authors may submit short videos to complement their Articles. Videos can be used to illustrate a laboratory technique, hardware prototype, or clinical presentation that would benefit from such an addition, or to visually communicate to the reader novel features, special steps in a procedure, pitfalls, or other information that may not be easily conveyed through text or a figure. Videos should be of high quality, no more than 5 minutes in length, and submitted as .mp4 files. Please do not send proprietary file types such as .wmv (Windows Media) and .rm (Real Media) files.

Authors of Articles will be prompted at submission to provide a brief summary of their work, not to exceed 100 words. In the event of acceptance, this will be recorded and included as an audio file in all online versions of the table of contents. The Audio Summary should address the following questions:

What was the paper about/what was the rationale for the study?
How did you approach the problem?
What were your findings?
What are the implications of the findings and how do they add to the field?
A simple phonetic spelling of the first author’s full name should also be provided.

Citation Classic

Citation Classics are typically invited submissions that highlight a landmark article in the field of clinical chemistry. In this feature, one of the authors of the original article provides some historical insights and anecdotal stories surrounding its publication.

Citation Classics should not include an abstract and are limited to 600 words, no more than 6 references, and no more than 5 authors. Generally, tables and figures are not permitted; however, if the text does not exceed 500 words, one table or figure will be allowed. Also, supplemental data are not permitted for Citation Classics.

Clinical Case Studies/Commentary

Clinical Case Studies are submitted directly from authors. These articles are intended to be educational, with the goal of helping to develop or improve problem-solving skills. Clinical Case Studies may report unusual (although not necessarily rare) biochemical manifestations of disease, atypical presentation of disease, situations where the laboratory helped in making or clarifying a diagnosis, or information that would be helpful in understanding the pathophysiology of a disease.

Two accompanying commentaries will introduce additional concepts that may be useful to readers, discuss confounding factors that might affect a diagnosis or analytical result, and/or provide comments about the case itself. Commentaries are invited and authored by clinical chemists, physicians, or scientists with expertise in the area.

A Clinical Case Study should not include an abstract. It should, however, include a case description followed by the case discussion, limited to 1,500 words total. References are limited to 10, and the tables and figures are limited to 2 in total. Authors should include 3-5 brief questions regarding the case that would stimulate discussion and learning about the disease state. These questions will be circulated to educational centers before publication. The author should also list up to 5 points to remember at the end of the manuscript. The questions and points are not included in the manuscript count of 1,500 words. The case should read as a bit of a mystery or diagnostic dilemma. The case title, case description, and questions should not disclose the diagnosis. Supplemental data are not permitted for Clinical Case Studies. No more than 5 authors should be listed.

Commentaries are limited to 300 words, with no more than 1-2 references. They should not include an abstract or tables and figures and should have no more than 5 authors. Supplemental data are not permitted for Commentaries.

Clinical Chemist

This monthly feature provides a forum for informing readers about general items of interest. Topics might include announcements for upcoming conferences, awards received by members of the AACC, announcements of new features in the journal, humorous items, artwork or photographs from readers, or general scientific news. Readers may submit items for consideration in the following categories: Unveiling the Right Side, What Is Your Guess?, Genetic Metabolic Series, and Clinical Toxicology Series, following the specific guidelines for each. The editors will make the final decision on the appropriateness and priority for inclusion in this section of the journal.

Please note that the journal is not currently considering unsolicited submissions to the Technology Corner, Science in the Arts, and Best of Clinical Chemistry sections.

Clinical Toxicology Series

The Clinical Toxicology Series falls under the Clinical Chemist and contains short clinical cases in toxicology. Each article will include a case description (no more than 75 words), 3 questions, a case discussion (no more than 250 words), and no more than 5 references.

Correction

Corrections are unique and will be considered on a case-by-case basis. Authors are encouraged to contact the Editorial Office (clinchemed@aacc.org) should they wish to submit a Correction or should they find a printer error that needs correcting.

Editorial

These are typically invited submissions. Editorials provide opinions and observations by an expert in the field about the subject matter or content of a scientific paper published in Clinical Chemistry. In addition to further educating readers on a selected topic, Editorials are designed to stimulate readers to formulate their own opinions about a paper and its value to the field. In some cases, Editorials may also be independent opinions and observations about a controversial topic or changes taking place in the field.

Editorials are limited to 1,500 words. They should not include an abstract. References are limited to 15, and tables and figures are not permitted. No more than 5 authors should be listed. Supplemental data are not permitted for Editorials.

Genetic Metabolic Series

The Genetic Metabolic Series falls under the Clinical Chemist and contains short clinical cases in biochemical genetics. Each article will include the actual case presentation, a chromatogram, the biochemical pathway of the defect, and a short case discussion. Submissions should not exceed 600 words in length and should include no more than 2 tables or figures and 5 references.

Inspiring Minds

These biographical articles are commissioned to present the achievements of distinguished clinical chemists, as well as their philosophical views on their professional life and the field of clinical chemistry.

Letter to the Editor/Reply

Letters are submitted directly from authors and can be used to report an observation or to discuss a previously published original Article. Letters in response to papers other than Articles will not be considered for publication. Letters report observations on interferences, suggestions to improve test performance, or other observations that are of importance to the wider audience. A Reply to a Letter may also be solicited by the editors. The one figure or table provided should be concise and should not be multipart (i.e., Fig. 1A, 1B, 1C, Part 1, Part 2).

A Letter to the Editor is limited to 750 words. It should not include an abstract. The references are limited to 5, and only 1 table or figure is permitted. Supplemental data are not permitted for Letters to the Editor.

A Reply is limited to 750 words. It should not include an abstract. The references are limited to 5, and only 1 table or figure is permitted. Supplemental data are not permitted for Replies.

Letters to the Editor and Replies should list no more than 8 authors, with any additional contributors listed in the Acknowledgments. Although exceptions are rare, you may email clinchemed@aacc.org detailing each author's contribution to your submission, which will be forwarded to the editor.

In some instances, editors may request that a submission of another article type to Clinical Chemistry be decreased to meet the requirements of a Letter to the Editor.

Looking to the Past

Looking to the Past falls under the Clinical Chemist. This feature is designed to look back at a prior article or topic in the field that still has relevance or links to current practice. Submissions should not exceed 750 words in length and should include no more than 5 references and 1 table or figure. 

Mini-Review

Mini-Review articles are typically invited submissions. Mini-Reviews are intended to provide a general overview of a topic. Basic information is provided, along with selected references that can aid the reader in obtaining additional information about the subject. The use of illustrative figures or tables is encouraged.

A Mini-Review article should consist of a structured abstract limited to 250 words with headings of Background, Content, and Summary. The text should not exceed 3,500 words. The manuscript should have no more than 40 references and a total of 4 tables and/or figures. Supplemental data are permitted for Mini-Review articles.

Mini-Reviews should list no more than 5 authors, with any additional contributors listed in the Acknowledgments. Although exceptions are rare, you may email clinchemed@aacc.org detailing each author's contribution to your submission, which will be forwarded to the editor.

News & Views

News & Views submissions fall under the Clinical Chemist section. These are brief pieces, typically an announcement or short overview of a subject that is of interest to readers. News & Views should be no more than 500 words, with a maximum of 1 table or figure. No more than 5 authors should be listed.

Opinion

Opinion articles are invited submissions that present the belief or personal view of the author(s) on a specific topic. An opinion implies a conclusion thought out yet open to dispute. Opinion articles are often a formal expression by an expert of his/her judgment or advice. Unlike Editorials and Letters to the Editor, Opinion articles do not comment on, or refer to, specific papers published in the journal.

An Opinion should not include an abstract and is limited to 1,500 words, 15 references, 1 table or figure, and no more than 5 authors. Supplemental data are not permitted for Opinions.

Perspective

These articles are invited submissions. Perspectives highlight a clinical, analytical, or basic science report that was published in a journal other than Clinical Chemistry but has implications for the practice of clinical chemistry.

Perspectives should not include an abstract. They are limited to 1,500 words, 5 references, 1 table or figure, and no more than 5 authors. Supplemental data are not permitted for Perspectives.

Point/Counterpoint

These articles are typically invited submissions from experts in a selected discipline and provide different viewpoints on a topic that may be controversial, lacks consensus in the scientific community, or may be of high public interest. In most cases an author or group of authors is asked to write the first half of the article, describing the importance of the topic, challenges to be addressed, current limitations, and/or unmet needs. A second author or group of authors is invited to provide a “Counterpoint” discussion of a different viewpoint or critical factors.

Point/Counterpoint submissions should not include an abstract. The manuscript is limited to 1,500 words, 15 references, and 1 table or figure. Supplemental data are not permitted for Point/Counterpoint.

Q&A

This invited feature is meant to highlight a timely and important issue, either clinical or analytical, through a series of questions posed to leaders in the field by a moderator. The moderator is required to include 1) an introductory paragraph and 2) the following for each expert: a high-resolution, publication-quality photograph, and the expert's professional title and institutional affiliation. Five to 8 questions may be posed to 3 to 5 experts with the moderator documenting the answers. Submissions are limited to 5,000 words. Please note that participant photos should follow these guidelines:

• TIF is the preferred format for images. PDF and PPT will also be accepted. JPG is not an allowed file type.
• Upload photographs as individual image files. Do not embed in the Word document or submit as multiple slides in a single PPT file.
• Resolution should be minimum 300 dpi. Lower resolution will result in a blurry appearance in print.
• Images should be professional headshots, if available. 
• Please include photographs with each revision submission.

Reflection

These articles are invited submissions. Reflections are authored by highly accomplished scientists in their field who have greatly contributed to science. Reflections will be reserved for special issues and will focus on the specific advancements the individual has made in his or her field.

Reflections are limited to 2,000 words and should not include an abstract. The references are limited to 20, and 1 table or figure is permitted. Supplemental data are not permitted for Reflections.

Review

Review articles are typically invited submissions. Reviews are intended to provide comprehensive coverage of a topic, including background clinical or analytical information, the relevance and importance of the subject matter, and potential future directions. The use of illustrative figures or tables is encouraged.

A Review article should consist of a structured abstract with headings of Background, Content, and Summary limited to 250 words. The text should not exceed 5,000 words. The manuscript should have no more than 75 references and a total of 6 tables and/or figures. Supplemental data are permitted for Review articles.

Reviews should list no more than 15 authors, with any additional contributors listed in the Acknowledgments. Although exceptions are rare, you may email clinchemed@aacc.org detailing each author's contribution to your submission, which will be forwarded to the editor.

Special Reports

Special Reports may be submitted directly by authors or invited by the journal. The types of papers that would be considered include consensus reports, guideline development, position statements, or evidence-based recommendations on test utilization or quality specifications. The editors may also decide to classify other miscellaneous submissions under this heading.

A Special Report should consist of a structured or unstructured abstract limited to 250 words. The main text should be no more than 5,000 words. The manuscript should have no more than 40 references and a total of 4 tables and/or figures. Supplemental data are permitted for Special Reports.

Special Reports should list no more than 20 authors, with any additional contributors listed in the Acknowledgments. Although exceptions are rare, you may email clinchemed@aacc.org detailing each author's contribution to your submission, which will be forwarded to the editor.

Unveiling the Right Side

Submissions should highlight the creative side of someone in the field of chemistry. This can be poetry, a short story, photographs, or other creative artwork. Submissions are limited to 400 words and/or one image, photograph, or poem. All submissions are subject to review. Cover letter should state interest in contributing to Unveiling the Right Side and must be submitted under the category of Clinical Chemist.

What Is Your Guess?

Submissions for this 1-page quiz should consist of an image or lab values, a case description (no more than 75 words), 3 questions, case discussion (no more than 75 words), and no more than 5 references. Cover letter should state interest in contributing to What Is Your Guess? and must be submitted under the category of Clinical Chemist.

What Is Your Guess? submissions should list no more than 5 authors. Although exceptions are rare, you may email clinchemed@aacc.org detailing each author's contribution to your submission, which will be forwarded to the editor.

Manuscript Preparation 

Author Contribution Requirements
Manuscript Guidelines
Submission/Publication Fees
Journal Categories
Title Page
Abstract
Text
Disclosures/Conflict of Interest
Acknowledgments
References
Tables
Figure Captions
Figures
Color
Supplemental Data (Supplemental Figures, Tables, Methods)

Author Contribution Requirements

General Guidelines

Clinical Chemistry follows the recommendations for authorship set out by The International Committee of Medical Journal Editors (ICMJE). In accordance with these recommendations, manuscripts are considered for publication with the understanding that each listed author must meet the following criteria:

Substantial contributions to the conception or design of the work; or the acquisition, analysis, or interpretation of data for the work; AND
Drafting the work or revising it critically for important intellectual content; AND
Final approval of the version to be published; AND
Agreement to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

Author limits may be imposed for certain submission types. Please review the specific requirements for your submission type. Please list only the allowed number of authors in the author list, with the remaining contributors listed in an Acknowledgment. Exceptions may be made at the discretion of the editor.

If more than one author should be considered as the first authors, or as the corresponding authors, please indicate this clearly in a footnote on the first page of the manuscript.

Any alterations made to the manuscript after submission must be approved by the editor. Authors may upload the request letter to the online submission system as a supplemental file or send the letter via e-mail to the Clinical Chemistry editorial office (clinchemed@aacc.org). The editor may contact any of the authors and/or contributors to ascertain whether they have agreed to any alteration.

The ICMJE Recommendations for the Conduct, Reporting, Editing, and Publication of Scholarly Work in Medical Journals state that contributors who do not meet all 4 criteria for authorship should be named in the acknowledgments.

Important contributions to an article should be recognized and appropriately attributed in that article.

Good medical writers and editors can make valuable contributions to the publication process, often improving the clarity of the communication, broadening the scope of literature review, providing an extra level of data review, adding balance and objectivity, and shortening the time needed for manuscript development.

The American Medical Writers Association (AMWA) believes that these important contributions deserve recognition.

Readers benefit from knowing about the involvement of professional writers and editors.

Disclosing the editorial contribution and the source of funding of the writer and editor allows the reader to make informed judgments about the objectivity of the article.

Note that the AMWA position statement recommends acknowledgment of pertinent professional or financial relationships as well as acknowledgment of the contributions of writers and editors.
It also recommends that the person being acknowledged be given the opportunity to grant or refuse permission for the acknowledgment.

Changing the Author List

Any change in authors and/or contributors after initial submission must be approved by all authors. This applies to additions, deletions, change of order to the authors, or contributions being attributed differently. If a change is made to the author list after submission or during any revision, the submitting author must send an e-mail to clinchemed@aacc.org explaining the reason for the change and copying all authors for their approval. Any additions or deletions must be made in the electronic submission record as well as on the manuscript itself. At revision, be sure to select "Yes, the authorship has changed" when prompted.

Group Authorship

If you are including the name of a group or consortium in your author list, please clearly identify the group members who can take credit and responsibility for the work as authors by listing them in a footnote or at the end of the manuscript. Please also provide email addresses for each listed group member, either in the manuscript or by emailing clinchemed@aacc.org. All members of the group named as authors should meet all four criteria for authorship, including approval of the final manuscript, and they should be able to take public responsibility for the work and should have full confidence in the accuracy and integrity of the work of other group authors. They will also be required as individuals to complete the author disclosure and contribution forms. This is in accordance with the recommendations of ICMJE.

Manuscript Guidelines

MS Word document (.doc or .docx) is required for all submissions.
All figures must be uploaded separately as Image Files in Tagged Image File Format (.tiff), Encapsulated Postscript (.eps) or PowerPoint (.ppt) with embedded fonts.
All submissions must be double-spaced, 1 inch margin, twelve-point font size in Arial, Helvetica, Times New Roman and Symbol font (for non-text characters).
All submissions must be page numbered.
All submissions must have line numbers included in the text.
Do not use headers or footers.
Use standard abbreviations and define all nonstandard abbreviations.
All submissions require a title page.
Reporting of Concentration Units:
Analyte concentrations will be expressed in the text in the traditional mass unit (mg/dL, ng/ml, and so forth) followed by the SI unit in parentheses. Exceptions would include those analytes in which SI units are used globally, such as electrolytes (use mmol/L for sodium, potassium, chloride, and CO2 values), or cases in which the traditional unit and the SI unit differ by only a factor of 1000 in both the numerator and denominator (e.g., ng/mL vs µg/L). In such cases, the unit of measure consistent with common practice will be used.
The unit of measure mg/L should be used only when referring to SI units or when national or international guidelines require or recommend that the concentration of an analyte be expressed in that unit of measure, such as for high-sensitivity C-reactive protein. The unit of measure U/L will be used for most enzyme activites.
Only traditional units will be used for tables and figures in the printed version of a report; SI conversion factors will be provided in legends. All tables and figures will also be presented in SI units. These tables and figures will be made available in online supplements to published articles and letters. Authors will provide both versions before final acceptance of a manuscript. SI units are available at Bureau International des Poids et Mesures.
Supplemental Data are accepted for online publication only and are limited by submission types (See Types of Submissions for details).
Follow the guidelines for length restrictions, abstract, reference, table and figure, and supplemental data limits as outlined in the chart below:

*Word limit consists of the body of the manuscript only; it does not encompass the title page, abstract, acknowledgments, references, tables, figure legends, figures, or Clinical Case descriptions, questions, and points to remember.

**Structured abstracts contain the headings (1) BACKGROUND, (2) METHODS, (3) RESULTS, (4) CONCLUSIONS for all applicable article types except for Reviews and Mini-Reviews. Abstracts for Reviews and Mini-Reviews contain the headings (1) BACKGROUND, (2) CONTENT, (3) SUMMARY.

***If a figure accompanies the paper, the image should not be multipart (i.e., Fig. 1A, 1B, 1C, Part 1, Part 2).

Submission/Publication Fees

Authors are not required to pay submission fees in order to submit their work to Clinical Chemistry. If color figures are present in the submission, authors of accepted papers may be required to pay a fee for color printing at the time of publication.

Clinical Chemistry offers the option of publishing under either a standard licence or an open access licence. Please note that some funders require open access publication as a condition of funding. If you are unsure whether you are required to publish open access, please do clarify any such requirements with your funder or institution.

Should you wish to publish your article open access, you should select your choice of open access licence in our online system after your article has been accepted for publication. You will need to pay an open access charge to publish under an open access licence.

Details of the open access licences and open access charges.

OUP has a growing number of Read and Publish agreements with institutions and consortia which provide funding for open access publishing. This means authors from participating institutions can publish open access, and the institution may pay the charge. Find out if your institution is participating.

Please note that you may be eligible for a discount to the open access charge based on society membership. Authors may be asked to prove eligibility for the member discount.

Journal Categories

Articles are grouped in the journal according to subject. Upon submission, authors are required to select the journal category that best describes their manuscript from the list indicated below:

Molecular Diagnostics and Genetics (MDG)
Evidence-Based Laboratory Medicine and Test Utilization (TUO)
Hemostasis and Thrombosis (HAT)
Proteomics and Protein Markers (PPM)
Cancer Diagnostics
Lipids, Lipoproteins, and Cardiovascular Risk Factors (LLP)
Drug Monitoring and Toxicology (DMT)
Hematology (HEM)
Endocrinology and Metabolism (END)
Point-of-Care Testing
Automation and Analytical Techniques (AAT)
Informatics and Statistics
Laboratory Management (LMA)
General Clinical Chemistry (GCC)
Animal Clinical Chemistry (ANI)
Clinical Immunology (CLI)
Pediatric Clinical Chemistry (PED)
Nutrition (NUT)
Infectious Disease
Other Areas of Clinical Chemistry (OTH)
Epidemiological Studies

Title Page

The first page of the manuscript should include the following information:

full title of submission, which should include only generic, not trade, names when describing a test, assay, etc.;
running head of fewer than 50 characters (including spaces);
list of all authors (first name, middle initial, and last name, in that order);
names of each author’s institution (for Q&As only, also include the professional title for each participating expert);
name, address, telephone and fax number, and e-mail address of the corresponding author;
keywords;
any previous presentation of the manuscript;
list of abbreviations, in order cited; and
list of any “Human Genes" discussed in the paper. For each gene, indicate the gene symbol and gene name approved by the HUGO Gene Nomenclature Committee. Include other name(s) that are used in the paper or are widely used in the literature for the gene.

Abstract (Structured and Unstructured) 

Structured abstracts should be formatted to include separate headings of: Background, Methods, Results, and Conclusions. For Mini-Review and Review articles the headings should be: Background, Content, and Summary. Both structured and unstructured abstracts are subject to a limit of 250 words.

Unstructured abstracts do not require separate headings.

Citation Classics, Clinical Case Study, Commentary, Editorial, Inspiring Minds, Letters to the Editor, Reply, Obituary, Opinion, Perspective, and Point/Counterpoint submissions do not require an abstract.

In addition to appearing at the beginning of the manuscript, abstracts must be uploaded to the abstract field of the Manuscript Metadata page online upon submission.

Text

The body of the manuscript should be written as concisely as possible and must not exceed the manuscript category word limits described herein. All pages must be double-spaced and all lines numbered. The body of the paper should include: Introduction, Materials and Methods, Results and Discussion.

Introduction - why was the study undertaken?
Materials and Methods - how was the study done?
Results - what did the study find?
Discussion - what might it mean, why does it matter, what next?
Full corporate names of manufacturers of materials should be utilized (omit Inc., Co., GmbH and similar words). After the first mention, use a shorter name (e.g., for Bio-Rad Laboratories, use Bio-Rad). Only the manufacturer’s name should be used, unless the item in question was a gift, in which case the city, state, and e-mail or website of the company should be included.

Reporting of Concentration Units: Analyte concentrations will be expressed in the text in the traditional mass unit (mg/dL, ng/ml, and so forth) followed by the SI unit in parentheses.

Use of human subjects requires a statement in the text indicating whether the procedures followed were approved by your institution's responsible committee or were in accordance with the current revision of the Helsinki Declaration and whether subjects gave informed consent.

Accession numbers for data sets or sequence reads that have been deposited in a public database should be provided in the Materials and Methods section of the text.

Where applicable, a ClinicalTrials.gov identifier for a registered clinical study should be listed both at the end of the abstract and at the first mention of the trial acronym in the main text.

Disclosures/Conflict of Interest

All authors are required to complete a full disclosure form upon submission. Please note that the form is not limited to those disclosures that constitute a potential conflict of interest. The disclosure form is electronic and completed during the submission process within the Bench>Press submission system. Disclosures should not be included in an Acknowledgment or elsewhere within the submitted manuscript file. All grants or other forms of research funding applicable to the report, as well as all relevant employment or leadership roles, consulting or advisory relationships, stock ownership, and patents occurring within the previous 36 months should be included in this form. The recipient(s) of all applicable grants or other funding must be specified. Failure to adhere to this guideline may result in a return of the submission to the author for correction.

In order to complete disclosures, register with Clinical Chemistry at http://submit.clinchem.org/cgi/registration using a valid e-mail address. Each author is required to be registered and must individually complete the disclosures. If you are registered under a different e-mail address from the one the submitting author has provided, you will not be able to access the disclosures. After registration, the system may take up to 15 minutes to refresh before the disclosure form appears.

Each author is expected to disclose any relevant financial relationships held personally within the last 36 months. Any companies or proprietary entities producing scientific services, which have an investment, licensing, or other commercial interest in the subject matter under consideration in the submitted manuscript, must be disclosed.

Such information is held in confidence while the manuscript is under review and does not influence the editorial decision on reports of research; upon acceptance, relevant information is added to the manuscript for publication.

Authors of editorials are expected to be free of significant financial associations with companies that may be affected by topics discussed in the manuscript and must also complete a full disclosure at the time of submission.

The American Medical Writers Association (AMWA) recognizes the valuable contributions of biomedical communicators to the publication team. Biomedical communicators who contribute substantially to the writing or editing of a manuscript should be acknowledged with their permission and with disclosure of any pertinent professional or financial relationships. In all aspects of the publication process, biomedical communicators should adhere to the AMWA code of ethics.

Acknowledgments

Acknowledgments are limited to 60 words and should follow the main text of the manuscript directly above the reference section in a separate paragraph heading labeled “Acknowledgments.” They should not appear as footnotes.

Do not include financial support, or other disclosure/conflict of interest information in the Acknowledgment. This information should be included in the Author Disclosure/Conflict of Interest form. If you include research funding in the Acknowledgment, you must specify which author or authors received the funding or if the funding was given to the group or institution. Editorial staff will transfer this information to the disclosure section prior to publication if the paper is accepted.

References

References should appear in a separate section directly following the body of the manuscript. The section must be labeled “References” with no additional punctuation. In-text citations should correspond to the numbered references in this list and should be formatted as follows: (1) or (1, 2).

Italic or boldface type is prohibited in the referenced citations.
List and number the references in the order that they appear in the text.
Do not use the MS Word document numbering tool. Number each reference manually with the numeral and a period, followed by a space.
For articles with more than seven authors, list the first six authors followed by "et al." For seven or fewer, list all authors.
Authors’ names are inverted (last name, first/second initial). Do not add periods or commas within an individual author name; however, separate author names with a comma and end the author list with a period (Smith J, Doe JJ, Adams B.).
Capitalize only the first word of the title or subtitle, and any proper names that are part of the title. The title should end with a period.
The Journal names should be abbreviated as indicated at PubMed. For a list of journal abbreviations, please visit: LinkOut Journals.
Do not add a period after the journal abbreviation, but continue with a space followed by the year.
The year should be followed by a semicolon and then the volume number, which is followed by a colon and then the page numbers. Delete redundant numbers, for example 1998;12:231-45.
Do not include the months in parentheses; this information is not needed.
Use inclusive page numbers for articles and book chapters.

Abstract and supplement numbers should be provided, if applicable. Citations of unpublished abstract books, manuscripts in preparation or under review, personal communications, and manufacturers’ information should only be cited in the text and should not appear in the reference list. Unpublished material should be cited in the text as “unpublished observations,” and written permission from the source is required. Personal communications should also be listed parenthetically and should contain the first initial and last name of the contact as well as the month and year of the communication. A copy of written permission from the contact to use the communication must also be provided. Published manuscripts and manuscripts that have been accepted and are pending publication should be cited in the reference list.

In-press references cited in the reference list must be accompanied by a copy of the cited manuscript and a letter of acceptance, or a complete author proof from the publisher. These resources should be uploaded as supplemental data along with the manuscript and other print materials.

The submission system will extract the references from the submitted MS Word document (.doc or .docx) to display in a hyperlinked HTML format as an aid for reviewers and editors. This linking option allows for the checking of the correct formatting and the accuracy of the citations.

Authors must check the linking of their references to PubMed during the “Ready for You to Proof” stage of submission. Correct linking of the references depends on strict adherence to Journal style as indicated.

Clinical Chemistry style is available in the Endnote reference formatting program. Endnote users please note that the reference output from Endnote may not be exact and should still be checked carefully against the examples listed below. In particular, journal names may not be abbreviated correctly in the output. If you have used PubMed for journal name abbreviations, it is recommended that you take the following steps:

Open the output style for Clinical Chemistry.
In the settings along the left of the style window, select Journal Names.
Set the Journal Names option to "Don't Replace."
Then, use "File - Save As" to save a copy with a new name.
Refer to the Endnote Help Center for further assistance.

Reference Style:

Journal article with seven or fewer authors:

1. Vermeersch P, Mariën G, Bossuyt X. A case of pseudoparaproteinemia on capillary zone electrophoresis caused by geloplasma. Clin Chem 2006;52:2309-11.

Journal article with more than seven authors:

2. Fiechtner M, Ramp J, England B, Knudson MA, Little RR, England JD, et al. Affinity binding assay of glycohemoglobin by two-dimensional centrifugation referenced to hemoglobin Alc. Clin Chem 1992;38:2372–9.

Abstract:

3. Hortin GL, King C, Kopp J. Quantification of rhesus monkey albumin with assays for human microalbumin [Abstract]. Clin Chem 2000;46:A140-1.

Editorial:

4. Demers LM. New biochemical marker for bone disease: is it a breakthrough? [Editorial]. Clin Chem 1992;38:2169–70.

Letter to the Editor:

5. Davey L, Naidoo L. Urinary screen for acetaminophen (paracetamol) in the presence of N-acetylcysteine [Letter]. Clin Chem 1993;39:2348–9.

Book Chapter:

6. Rifai N, Warnick GR. Lipids, lipoproteins, apolipoproteins, and other cardiovascular risk factors. In: Burtis CA, Ashwood ER, Bruns DE, editors. Tietz textbook of clinical chemistry and molecular diagnostics. 4th Ed. St. Louis (MO): Elsevier Saunders; 2006. p. 903-81.

Thesis:

7. Haughton MA. Immunonephelometric measurement of vitamin D binding protein [MAppSci thesis]. Sydney, Australia: University of Technology, 1989:87pp.

Books and Monographs (serial volumes should be treated as journals):

8. Harrell FE Jr. Regression modeling strategies. New York (NY): Springer; 2001.

9. Bailar JC III, Mosteller F, editors. Medical uses of statistics. 2nd Ed. Boston (MA): NEJM Books; 1992:449 p.

Published Ahead of Print:

10. Milbury CA, Li J, Makrigiorgos GM. PCR-based methods for the enrichment of minority alleles and mutations. [Epub ahead of print] Clin Chem February 6, 2009 as doi:10.1373/clinchem.2008.113035.

Supplement:

11. Castelli WP. Lipids, risk factors and ischaemic heart disease. Atherosclerosis 1996;124 Suppl:S1-9.

Internet Source:

12. American Association for Clinical Chemistry. AACC continuing education. http://www.aacc.org/education-and-career/continuing-education (Accessed June 2016).

Preprint:

13. Mao Q, Chin R, Xie W, Deng Y, Xu H, Zhang RY, et al. Advanced whole genome sequencing and analysis of fetal genomes from amniotic fluid. Preprint at https://www.biorxiv.org/content/early/2017/08/08/173807 (2017).

Clinical Chemistry Trainee Council Webcasts and Pearls of Laboratory Medicine:

14. Browning T. Vitamin D. April 2012. Available from: http://www.traineecouncil.org/pearl (Clinical Chemistry Trainee Council, Pearls of Laboratory Medicine).

Tables

Tables are considered text. They should appear embedded as part of the submission directly following the reference section. Each table should appear on an individual page. Manuscripts will be returned to authors if the tables are uploaded as separate table files. (Manuscripts will not be returned for this reason if tables have been uploaded as supplemental data or if they are to be considered figures, in the special circumstances described below.)

Each table should be clearly labeled and numbered consecutively with Arabic numerals (Table 1, Table 2, etc.). The abbreviations used must be defined. As with the text, reporting of concentration units consists of analyte concentrations expressed in the text in the traditional mass unit (mg/dL, ng/ml, and so forth) followed by the SI unit in parentheses.

Tables should not be divided into parts. Separate parts (Table 1A, Table 1B, etc.) will be considered separate tables and will count toward your overall table/figure count.

Table captions should be limited to 60 words.

Each column of an individual table must have a heading and be clearly defined. Indicate explanatory footnotes with superscript lowercase italic letters in alphabetical order.

Tables will be converted into a standard format for publication that will not include color. Large or complex tables or tables that include graphic elements should be submitted as figures or as supplemental data for online publication only. The Editor may choose to make any table supplemental as he/she deems necessary.

If a table has been published previously, acknowledge the original source in the table caption. You must obtain written permission from the copyright holder to reproduce the table and upload this permission as supplemental data. Please specify whether the table has been exactly reproduced or adapted from the original source, and provide a copy of the original table if it has been adapted. Even if the table has been modified, it may still require a permission. Any costs associated with table permissions will be borne by the author. Contact the editorial office (clinchemed@aacc.org) if you are not sure whether permission is needed.

Figure Captions

Figure captions and sub-captions must be listed together on an individual page directly following the tables or the references if the submission does not include tables. Each figure requires a figure caption and should be clearly labeled (Figure 1, Figure 2, etc.). Multi-panel figures and figures with parts (a, b, c, etc.), should be distinctively labeled (Figure 1A, Figure 1B, Figure 2A, etc.).

Figure captions should be limited to 60 words.

If a figure has been published previously, acknowledge the original source in the figure caption. You must obtain written permission from the copyright holder to reproduce the figure and upload this permission as supplemental data. Please specify whether the figure has been exactly reproduced or adapted from the original source, and provide a copy of the original figure if it has been adapted. Even if the figure has been modified, it may still require a permission. Any costs associated with figure permissions will be borne by the author. Contact the editorial office if you are not sure whether permission is needed.

Figures

All figures must be uploaded separately as image files in Tagged Image File Format (.TIFF) or Encapsulated Postscript (.EPS). Microsoft Power Point (.PPT) is also acceptable; however, the graphics must contain embedded fonts with one image per slide, one slide per file. Each image should have a resolution of 600 dots-per-inch (dpi). More detailed specifications can be found on our print publication vendor’s page at Cenveo Digital Art Support.

The submission system is designed to retrieve the manuscript file and separate image file(s) and combine or merge the files into an individual Portable Document Format (.PDF) for reviewing purposes. It is the responsibility of the author to verify the quality of the image file(s) after the conversion to PDF. It may be necessary to alter the individual image file(s) to ensure the content is not lost or misconstrued in the merged PDF.

Submissions will be returned to authors if the figures are embedded within the manuscript file and not uploaded separately or if the figures have become illegible in the merged PDF.

Do not place unnecessary graphics, such as borders, in or around your figure. Pay particular attention to the quality of the lines, symbols, and patterns. Published figures are reduced to 1 column (85mm) or 2 columns (176 mm) in width. If, at that width, the figure symbols or lettering are not clear, you will need to increase the font size. Letters should be 8-10 points when reduced, and subscripts no less than 6 points. Initial capitals and lower case letters and a medium (not bold) sans serif font are required. European PI, Helvetica, Mathematical PI, Times Roman, and Symbol fonts are Type 1 PostScript fonts supported by our printer for the creation of digital art figures.

The x-axis and y-axis should be clearly labeled, and the units of measurements given. This includes using decimal points instead of commas, italicizing species or gene symbols, and using U.S. English.

Color

The costs of publishing color illustrations in print will be borne by the author. Costs are $1500 for the first print color figure and $500 for each subsequent figure, or parts of figures extending onto multiple pages for Articles, Special Reports, and Letters to the Editor. Color versions of figures may be provided for publication in the online Journal at no extra charge. Upon acceptance, authors will have the opportunity to request online-only color printing and will be billed for the color costs unless otherwise requested. If black and white printing is requested, color figures alone should still be submitted to the Journal. The figures will be converted to grayscale by the printer. Authors should not attempt to convert the figures or submit both color and grayscale versions.

Supplemental Data (Supplemental Figures, Tables, Methods)

Figures or tables too large for print, manuscript material that exceeds the limitation for the specific submission type, or appendices should be submitted for online publication only. These files should be marked and uploaded separately as supplemental files during submission and should be referenced within the text as supplemental data (i.e., "Supplemental Table 1," "Supplemental Figure 1"). Grouping all Supplemental tables, figures and text together into one or two files is preferred. Supplemental files must be labeled and referred to consecutively in the main text (i.e., Supplemental Table 1, Supplemental Table 2, Supplemental Figure 1, Supplemental Figure 2). Supplemental files must be provided in formats that are widely accessible to readers. Many readers of the Journal do not have access to the programs needed to open .eps figures, so do not use .eps format in a supplemental file.

All supplemental figures/images must have a caption embedded within the supplemental figure. All supplemental tables must have a title embedded within the supplemental table. All supplemental methods must have a title embedded within the supplemental text. Do not include the supplemental figure captions in the main text of the manuscript.

When labeling your files and referencing them within the main text, name them “Supplemental” and do not add the word “Data” (i.e., “Supplemental Table 1,” not “Supplemental Data Table 1” or “Supplementary Table 1”). If all Supplemental Figures or all Supplemental Tables are contained in a single file, that file should be referred to as "Supplemental Figures" or “Supplemental Tables.”

Please be advised, supplemental data are permitted for Article, Inspiring Minds, Mini-Review, Review, and Special Report submissions only. Manuscripts of all other types with supplemental data will be returned to authors.

Supplemental data will be reviewed as part of the manuscript and will be evaluated for its importance and relevance; however, it should not appear in the “Peer-reviewed PDF” file created by the submission system.

If accepted and posted online, the supplemental data will be referenced in the text of the print article directing readers to the website.

Online Submission and Tracking

What is Bench>Press?
Registering
Changing Contact Information and Password
Troubleshooting
Journal Portal

What Is Bench>Press?

Clinical Chemistry uses the Bench>Press™ (B>P) manuscript submission, tracking, review, and publishing system, developed by Stanford University Libraries' HighWire Press.

B>P is an Internet application and operates with standard browsers, although a JavaScript-enabled browser (such as Internet Explorer) is recommended.

For user convenience and accessibility, B>P converts uploaded manuscript files to Adobe Portable Document Format (PDF). Adobe Acrobat Reader is required to view these files and is available at no cost.

B>P uses a series of pages, presented one at a time, to guide the author through the submission process. For help during regular business hours, contact Clinical Chemistry via e-mail (clinchemed@aacc.org).

Registering

Please see FAQs for more extensive help.

Before submitting a manuscript or review of a manuscript, you must register with our manuscript submission and tracking system. 

After accessing the registration page, you will need to verify your e-mail address. If there is an existing account with an old e-mail address, do not create a new account with a different e-mail address. Simply access the account with the out-of-date e-mail address, and use the system to update/change your e-mail address.

Always use the same e-mail when accessing the system. Multiple e-mail addresses will cause repeated registrations and the creation of multiple accounts, which could lead to future system access problems.

NOTE: If you have used other Bench>Press journals, you must use the same e-mail address and password to register with Clinical Chemistry. Although all Bench>Press journals require the same e-mail address and password for access, this is the only shared information. You must be registered individually with each journal you are trying to access.

Changing Contact Information and Password

E-mail addresses, passwords, and other contact information can be modified at any time by clicking "Personal Info" from the gray navigation bar at the top of any page within the manuscript processing system.

Feel free to contact the Editorial Office via e-mail (clinchemed@aacc.org)should you need assistance.

Troubleshooting

Please see FAQs at for more extensive help.

Trouble Registering

All authors and reviewers must be registered with Clinical Chemistry. To register, go to http://submit.clinchem.org, and click the “Create a New Account” button to the left of the login screen. If you do not receive a request to create a password and answer a security question, you are most likely registered with Clinical Chemistry or another Bench>Press journal. Clinical Chemistry uses an online manuscript management system called Bench>Press. Bench>Press is used by hundreds of journals, all of which share the same registration system. If you have already registered with another Bench>Press journal, you do not need to repeat the registration process. You simply need to sign in with the same e-mail and password and complete a profile page for Clinical Chemistry.

If you can't remember with which journal(s) you registered, this information can be sent by clicking the "Send My Registration Details" button on the registration page.

No e-mail response after registering:

If you have registered and have not received a verification e-mail, this may be due to a spam blocking filter associated with your institutional server. You may need to manually register clinchemed@aacc.org so as to accept mail from Clinical Chemistry. Your Systems Manager should be able to help you with this problem.

Java Difficulties:

If you are using Internet Explorer as your browser and are having trouble accessing pages, you might want to try the following:

Tools

Internet Options
Advanced
Under heading Microsoft VM, make sure all 3 boxes are checked:
Java console
Java logging
JIT Compiler
Click okay.
Restart machine
You may check to see if the site works properly by going to http://submit.clinchem.org/.

Please note that login information (e-mail and password) for the submission and review site will not be the same login information you use if you subscribe to the online journal.

Duplicate Accounts:

Often, due to problems with the initial registration or infrequent use, an author may have two accounts listed. Multiple accounts lead to future system access problems and therefore must be merged.

If an author or reviewer suspects this is the problem, send a request with the preferred e-mail address, current contact information, and the suspected invalid e-mail address to the Clinical Chemistry editorial office (clinchemed@aacc.org).

Cookies preventing login:

Bench>Press requires users to have their browser set to accept cookies in order to maintain their logged-in status throughout the system. A "cookie" is a message given to a browser by a server. The browser stores the message, and the message is sent back to the server each time the browser requests a page from the server.

If the user does not have cookies enabled, the user will be required to repeatedly sign in to the system.

Most browsers will allow the user to manually alter the cookie settings from the Tools or Internet Options bar.

Expertise Terms:

The Area of Expertise list was developed to help editors choose reviewers who possess specific knowledge in a given area.

Our tracking system has been set to allow this page to appear---as a gentle reminder---until the reviewer has selected at least one item on the list. As soon as the reviewer selects a topic and saves it, it will no longer appear.

Changing these areas of expertise or adding more detailed information can be accomplished by simply logging into our website at any time and clicking the Personal Info area at the top of the page.

On the lower right side of the page, the user will find "Expertise Terms: Edit Expertise Terms." Click on this link and change the data accordingly.

Conversion Errors:

Receiving a conversion error means that conversion of your manuscript to PDF format has failed.

Invalid file types are the most common cause of conversion failure. Be sure your file names end with extensions appropriate to the file type (i.e. ".doc", ".tif" or ".eps"). Mac computers generally leave off the file type extension and it must be added manually.

Formats that are not supported include the following: Bitmap (.bmp), PICT (.pict), Excel (.xls - Excel tables can be embedded in word processing documents), Photoshop (.psd), Canvas (.cnv) and CorelDRAW (.cdr). Multi-slide PowerPoint files (.ppt). If any of these have been used to create your file, you will need to convert the file to an acceptable file format for submission in order for the files to convert properly.

Large or numerous files may slow the conversion process of submission, sometimes resulting in a system "time out" or conversion failure. It may be appropriate to upload and wait for the conversion of an individual file before proceeding with the remaining files. The Bench>Press submission and tracking system has limits of how much data can be uploaded at one time. Generally most files become unwieldy when they pass the 1 MB (megabyte) mark.

For reference:

1000 Bytes (B) = 1 Kilobyte (KB)
1000 Kilobytes (KB) = 1 Megabyte (MB)
1000 Megabytes (MB) = 1 Gigabyte (GB)

Empty HTML references field:

You may find that your HTML references section is empty. This can be remedied by including the heading "References" before the references section in your paper.

HTML references cannot be edited directly; any changes must be made by re-uploading your manuscript file during the proofing stage.

In addition, uploading a PDF file as your manuscript source file will prevent the references from parsing to the Clinical Chemistry HTML reference window.

Journal Portal

In the event that your paper is rejected, you may be interested in submitting it to Clinical Chemistry’s sister journal, The Journal of Applied Laboratory Medicine (JALM). Authors of a manuscript rejected by Clinical Chemistry will receive a decision email with detailed instructions on the Journal Portal, a tool that allows authors to easily transfer their papers to JALM for consideration. Authors will have 30 days to complete the transfer before the portal closes for each manuscript. The portal can be accessed through the Author Area in the “Manuscripts with Decisions in the Past 180 Days” queue.

The following information will be transferred from Clinical Chemistry to JALM:

Author disclosures
Author Contributions
Blinded Clinical Chemistry reviewers’ comments for authors, if there are any. Comments for the editors will not be transferred.

Authors who wish to transfer their submissions should review the JALM Information for Authors for more detailed information and submission requirements.

Post-Acceptance 

Copyright
Proofs
Disclaimers
Permissions and Reprints
Advance Articles

Copyright

Upon acceptance, all authors are required to read and sign the Copyright Transfer Agreement. Each author will receive an email from Oxford Academic inviting them to sign a statement confirming that the manuscript does not contain material for which publication would violate any copyright or other personal or proprietary right of any person or entity. U.S. Federal employees will need to be identified. Each author must be registered with our online submission system to access, read, and electronically sign the copyright agreement.

Manuscripts will be held until all copyrights are received. In the event that copyrights are not received, the manuscript will not be published.

Manuscripts will not be prohibited from publication solely on the basis of a web-posting of a talk at a medical or scientific meeting that presents all or part of the content of the submitted manuscript.

Authors are expected to retain – for a minimum of 1 year after publication – the raw data from laboratory or clinical studies and to present these data upon request of the Editor if the data are contested.

Authors are expected to identify to the Editor any other manuscripts (in print, accepted, have been submitted, in preparation) that relate to the submitted manuscript, especially if any patients or results are described in both.

Questions related to the possibility of perceived redundant publication or fragmentation of results should be directed to the Editor.

Proofs

To find out the status of your accepted paper in the publication process, including when you can expect to receive your proof, please email jnls.author.support@oup.com.

Disclaimers

Manuscripts published in Clinical Chemistry reflect the individual views of their authors and, in the absence of a statement to the contrary, not the views of the institutions with which the authors are affiliated. The contents of advertisements or articles are not to be construed as official statements, evaluations, or endorsements by the Editor or the American Association for Clinical Chemistry.

Permissions and Reprints

Clinical Chemistry is copyrighted by the AACC. Permission to reproduce copyrighted material for scholarly or commercial use can be arranged through Oxford University Press.

E-mail: journals.permissions@oup.com

Advance Articles

Accepted articles are published online after copy editing and author review of corrected proofs.

Clinical Chemistry Editorial Office

Clinical Chemistry
900 Seventh Street, NW
Suite 400
Washington, DC 20001
United States

clinchemed@aacc.org
(202) 420-7678
(202) 833-4576 [FAX]

Sheehan Misko, Director: smisko@aacc.org
Kristen Hauck, Managing Editor: khauck@aacc.org
Patty Brady, Senior Editorial Specialist: pbrady@aacc.org
Erin Roberts, Editorial Specialist: eroberts@aacc.org

Please include the corresponding author's e-mail address and the manuscript number on all correspondence.