Most medical journals use AMA (American Medical Association) style, but some require NLM/Vancouver or APA formatting. The core elements are the same across all three: authors, article title, journal name, year, volume, issue, pages, and a DOI when available. The differences come down to punctuation, author limits, and how you handle digital identifiers.
AMA Style (Most Medical Journals)
AMA style, now in its 11th edition, is the default for most biomedical publications. The basic pattern for a print journal article looks like this:
Author AA, Author BB. Title of article. Journal Abbreviation. Year;Volume(Issue):Pages.
A real example: Halpern SD, Ubel PA, Caplan AL. Solid-organ transplantation in HIV-infected patients. N Engl J Med. 2002;347(4):284-287.
A few formatting details trip people up. The article title uses sentence case (only capitalize the first word and proper nouns), and it’s never italicized. The journal name is abbreviated and italicized. There are no spaces between the year, volume, issue, and page numbers. They’re compressed into one string: 2002;347(4):284-287.
For articles accessed online, add the DOI at the end with no period after it. If there’s a DOI, you don’t need a URL. If you’re citing something that only has a URL and no DOI, include an accessed date before the link.
Author AA, Author BB. Title of article. Journal Abbreviation. Year;Volume(Issue):Pages. doi:10.xxxx/xxxxx
For author lists, include all names unless there are more than six. If there are seven or more, list the first three followed by “et al.” Some online-only journals don’t have page numbers. In that case, use the article number instead.
NLM/Vancouver Style
NLM (National Library of Medicine) style, sometimes called Vancouver style, is what PubMed uses internally and what many international medical journals require. It looks similar to AMA but has its own quirks.
Author AA, Author BB. Title of article. Journal Abbreviation. Year Mon Day;Volume(Issue):Pages.
A real example: Halpern SD, Ubel PA, Caplan AL. Solid-organ transplantation in HIV-infected patients. N Engl J Med. 2002 Jul 25;347(4):284-7.
The most visible difference from AMA: NLM includes the publication date (month and sometimes day) before the volume number. The journal abbreviation is not italicized. Page numbers are compressed, so 284-287 becomes 284-7. If a journal uses continuous pagination across an entire volume (common in medicine), you can drop the month and issue number entirely.
For author lists, NLM previously used “et al.” after six authors. The current recommendation is to list all authors, though listing the first six followed by “et al.” remains acceptable.
Online articles in NLM style look different from the other formats:
Author AA. Title. Journal Abbreviation [Internet]. Year Mon [cited Year Mon Day];Volume(Issue):Pages. Available from: URL
You can also append database identifiers like PubMed PMIDs or PMCIDs at the end of any NLM citation.
APA Style
APA (American Psychological Association) style, now in its 7th edition, is less common in clinical medicine but standard in psychology, nursing, public health, and health education journals. The format differs more noticeably from AMA and NLM.
Author, A. A., & Author, B. B. (Year). Title of article. Journal Name, Volume(Issue), Pages. https://doi.org/xxxxx
APA uses the full journal name rather than an abbreviation, italicizes both the journal name and volume number, and places the year in parentheses right after the authors. Two key rules: always include the issue number, and always include the DOI when one exists. The DOI is formatted as a full URL (https://doi.org/…) with no period after it.
Finding the Correct Journal Abbreviation
Both AMA and NLM style require abbreviated journal titles, and getting the abbreviation wrong is one of the most common citation errors. “The New England Journal of Medicine” becomes “N Engl J Med.” “The Journal of the American Medical Association” becomes “JAMA.”
The official source is the NLM Catalog, searchable at ncbi.nlm.nih.gov/nlmcatalog/journals. Type in any journal name and you’ll get its standard ISO abbreviation. This is the same database that PubMed uses, so it covers virtually every biomedical journal you’d need to cite.
Citing Preprints
Preprints from servers like medRxiv or bioRxiv aren’t peer-reviewed, so they need to be clearly labeled. The general approach across styles is to treat them like unpublished manuscripts with an added repository location and DOI. In NLM style, it looks like this:
Author AA, Author BB. Title. Repository Name [Preprint]. Date [cited Date]. Available from: https://doi.org/xxxxx
The word “Preprint” in brackets is the critical piece. It signals to readers that the work hasn’t been through peer review. Always include the DOI so readers can check whether the preprint has since been published as a final article.
Citing Retracted Articles
If you need to cite a paper that has been retracted, mark it clearly in the reference. Add “RETRACTED:” before the article title so readers immediately know the status of the work. For example:
Author AA, Author BB. RETRACTED: Title of article. Journal Abbreviation. Year;Volume(Issue):Pages.
There are legitimate reasons to cite retracted papers, particularly when writing about research integrity or documenting what was previously reported. But if a retracted paper was supporting a factual claim in your manuscript, replace it with a different source.
Quick Reference: Key Differences
- Author limits before “et al.”: AMA uses 3 of 7+; NLM traditionally uses 6 of 7+; APA uses up to 20
- Journal name: AMA and NLM use abbreviations; APA uses the full name
- Italics: AMA italicizes the journal abbreviation; NLM does not; APA italicizes the journal name and volume number
- Date placement: AMA and NLM put the year after the journal name; APA puts it in parentheses after the authors
- DOI format: AMA uses “doi:10.xxxx”; APA uses “https://doi.org/10.xxxx”; NLM uses “doi:” followed by the number
- Period after DOI: None of the three styles place a period after the DOI
Recent Updates Worth Knowing
The AMA Manual of Style added new guidance in February 2025 covering two increasingly common situations: how to cite results from online database searches and how to handle content generated by AI tools like large language models. If your manuscript involved either of those, check sections 3.15.12 and 3.15.13 of the updated manual for the specific formatting requirements your journal will expect.