Medical publishing operates under standards that most other academic disciplines never have to think about. A misattributed drug dosage study, an incorrectly cited clinical trial, or a garbled reference to a treatment guideline is not merely an administrative failure — it can propagate through the literature and, in the worst cases, inform clinical decisions. Journals like The Lancet, JAMA, and NEJM enforce citation rules with the same rigour that peer reviewers apply to methodology sections, because in medicine, provenance is clinical infrastructure.
Three citation styles dominate medical publishing: Vancouver (the system codified by the International Committee of Medical Journal Editors, ICMJE), AMA (the style of the American Medical Association, now in its 11th edition), and the NLM format (from the U.S. National Library of Medicine, widely used in systematic reviews and PubMed-indexed work). Understanding when to use each — and the specific rules that distinguish them — is foundational for anyone writing for clinical or biomedical journals.
Vancouver is the most widely adopted citation system in medicine. It takes its name from a 1978 meeting of journal editors in Vancouver, Canada, and is maintained today through the ICMJE Recommendations for the Conduct, Reporting, Editing, and Publication of Scholarly Work in Medical Journals (ICMJE, 2023). The system uses numbered references inserted in-text as superscripts or in parentheses, in the order they are first cited. The reference list is numbered sequentially — not alphabetical. Most major clinical journals, including BMJ, Lancet, NEJM, and JAMA, follow Vancouver or a close variant.
https://doi.org/xxxxx.PMID: 35781234.Journal article:
Yancy CW, Jessup M, Bozkurt B, Butler J, Casey DE Jr, Drazner MH, et al. 2013 ACCF/AHA guideline for the management of heart failure. J Am Coll Cardiol. 2013;62(16):e147–239. https://doi.org/10.1016/j.jacc.2013.05.019
Book:
Kasper DL, Fauci AS, Hauser SL, Longo DL, Jameson JL, Loscalzo J, editors. Harrison's Principles of Internal Medicine. 20th ed. New York: McGraw-Hill Education; 2018.
Clinical guideline:
National Institute for Health and Care Excellence. Hypertension in adults: diagnosis and management. NICE guideline NG136. London: NICE; 2019. Available from: https://www.nice.org.uk/guidance/ng136
Cochrane review:
Hartling L, Milne A, Hamm MP, Vandermeer B, Ansari M, Tsertsvadze A, et al. Testing the Newcastle Ottawa Scale showed low reliability between individual reviewers. J Clin Epidemiol. 2013;66(9):982–93. https://doi.org/10.1016/j.jclinepi.2013.03.003
The AMA Manual of Style: A Guide for Authors and Editors (11th edition, 2020) governs publications of the American Medical Association and its associated journals, including JAMA and its specialty journals. Like Vancouver, AMA uses superscript numerals for in-text citations in order of appearance. The two systems look superficially similar but diverge in important formatting details that editors notice immediately.
2020;324(5):456-464 — note no space before the semicolon, issue in parentheses, pages with a hyphen (not an en dash).doi:10.xxxx/xxxxx (AMA uses the doi: prefix rather than the full URL, though either is acceptable in practice).Key difference — et al. threshold: Vancouver uses et al. after six authors (i.e., seven or more triggers it). AMA uses et al. after three authors (i.e., four or more triggers it). Applying the wrong rule is among the most common errors in manuscripts that cross between the two styles.
Journal article:
Antman EM, Cohen M, Bernink PJ, et al. The TIMI risk score for unstable angina/non-ST elevation MI. JAMA. 2000;284(7):835-842. doi:10.1001/jama.284.7.835
Book:
Townsend CM Jr, Beauchamp RD, Evers BM, Mattox KL, eds. Sabiston Textbook of Surgery: The Biological Basis of Modern Surgical Practice. 21st ed. Elsevier; 2021.
Clinical guideline:
American Diabetes Association Professional Practice Committee. Standards of Care in Diabetes—2024. Diabetes Care. 2024;47(suppl 1):S1-S321. doi:10.2337/dc24-SINT
Cochrane review:
Sterne JAC, Savović J, Page MJ, et al. RoB 2: a revised tool for assessing risk of bias in randomised trials. BMJ. 2019;366:l4898. doi:10.1136/bmj.l4898
The NLM citation format is defined in Citing Medicine: The NLM Style Guide for Authors, Editors, and Publishers (2nd ed., Patrias & Wendling, 2007, updated continuously online at ncbi.nlm.nih.gov/books/NBK7256/). NLM is the authoritative source for how citations are structured in PubMed and MEDLINE. It is particularly prevalent in systematic reviews, evidence syntheses, and work produced or funded by U.S. federal health agencies (NIH, CDC, AHRQ). Cochrane Reviews and many systematic review databases use NLM conventions as their baseline.
PubMed PMID: 18678535.[cited 2024 Mar 12].Key difference — PMID emphasis: Of the three styles, NLM most explicitly calls for PMID inclusion. Vancouver allows it; AMA rarely includes it. For work that will be indexed in PubMed or shared in systematic review databases, NLM's PMID convention significantly improves traceability.
Journal article:
Moher D, Liberati A, Tetzlaff J, Altman DG; PRISMA Group. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. PLoS Med. 2009;6(7):e1000097. doi: 10.1371/journal.pmed.1000097. PubMed PMID: 19621072.
Book:
Straus SE, Glasziou P, Richardson WS, Haynes RB. Evidence-Based Medicine: How to Practice and Teach EBM. 5th ed. Edinburgh: Elsevier; 2019. 312 p.
Clinical guideline:
World Health Organization. WHO guidelines on physical activity and sedentary behaviour. Geneva: World Health Organization; 2020 [cited 2024 Jan 10]. Available from: https://www.who.int/publications/i/item/9789240015128
Cochrane review:
Higgins JPT, Thomas J, Chandler J, Cumpston M, Li T, Page MJ, et al., editors. Cochrane Handbook for Systematic Reviews of Interventions version 6.4. Cochrane; 2023 [cited 2024 Feb 5]. Available from: https://training.cochrane.org/handbook
All three styles draw on the same controlled vocabulary for journal abbreviations: the NLM Catalog (catalog.nlm.nih.gov), which is the official source for MEDLINE/PubMed journal title abbreviations. The abbreviations follow ISO 4 conventions with NLM-specific modifications.
Key points for practice:
TA field, making them a reliable source when checking abbreviations quickly.Practical shortcut: Export citations directly from PubMed in the "NLM" or "Vancouver" format. The exported file will contain the verified journal abbreviation, PMID, and DOI — eliminating the most common source of transcription errors.
| Element | Vancouver (ICMJE) | AMA 11th ed. | NLM |
|---|---|---|---|
| DOI | Recommended | Required (when available) | Recommended |
| DOI format | https://doi.org/xxx |
doi:xxx |
doi: xxx |
| PMID | Optional | Rarely included | Explicitly encouraged |
| PMID format | PMID: xxxxxxxx |
— | PubMed PMID: xxxxxxxx |
Including both PMID and DOI is never wrong in any of the three styles, and for systematic review work it is strongly advisable. DOIs resolve to the published version; PMIDs resolve to the PubMed record, which contains abstract, MeSH terms, and related article links — both serve different downstream needs.
The decision is usually made for you: submit to JAMA, follow AMA. Submit to BMJ or Lancet, follow Vancouver. Produce a Cochrane-registered systematic review, follow NLM with PRISMA conventions. When no journal style is specified, Vancouver is the default assumption in most clinical and biomedical contexts, given its ICMJE backing and near-universal adoption among peer-reviewed medical journals worldwide.
For authors switching between styles — or writing for an interdisciplinary audience that includes both medical and social-science readerships — the critical points to track are the et al. threshold and DOI format. Everything else can be corrected at the copyediting stage; incorrect author-count rules tend to be caught in peer review and read as a signal that the manuscript was not proofread carefully.
Manual adherence to Vancouver, AMA, or NLM rules — across every journal abbreviation, author-count threshold, and DOI format — is one of the most time-consuming parts of preparing a manuscript or systematic review. DEEPNOTIS addresses this directly: paste a DOI or PMID and the platform auto-enriches the citation with verified metadata pulled from PubMed and CrossRef, including the correct NLM journal abbreviation, full author list, volume, issue, pages, and both PMID and DOI identifiers.
Switch between Vancouver, AMA, and NLM output formats with a single click — the underlying data stays consistent while the formatting adapts to whichever style your target journal requires. For systematic reviews with hundreds of references, citation labels allow you to organize sources by study design, risk-of-bias rating, or PICO element before exporting the final reference list.
Getting the citation format right is not optional in medical publishing. Having a tool that enforces it automatically is what makes it tractable at scale.
International Committee of Medical Journal Editors. (2023). Recommendations for the conduct, reporting, editing, and publication of scholarly work in medical journals. http://www.icmje.org/icmje-recommendations.pdf
Iverson C, Christiansen S, Flanagin A, et al. AMA Manual of Style: A Guide for Authors and Editors. 11th ed. Oxford University Press; 2020. https://doi.org/10.1093/jama/9780190246556.001.0001
Patrias K; Wendling D, technical editor. Citing Medicine: The NLM Style Guide for Authors, Editors, and Publishers [Internet]. 2nd ed. Bethesda (MD): National Library of Medicine (US); 2007 [updated 2015 Oct 2; cited 2024 Mar 1]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK7256/
National Library of Medicine. NLM Catalog: Journals referenced in the NCBI databases [Internet]. Bethesda (MD): NLM; [cited 2024 Mar 1]. Available from: https://www.ncbi.nlm.nih.gov/nlmcatalog/journals