AMA citation style is the standard reference format for medical journals, health sciences publications, nursing research, and clinical manuscripts. Developed by the American Medical Association and codified in the AMA Manual of Style, 11th edition (2020), it is required by thousands of biomedical journals worldwide — including JAMA, the Annals of Internal Medicine, and the Archives series — as well as by most medical schools for student papers and research reports.
AMA uses a numbered superscript citation system: each source is assigned a number the first time it is cited, and that number appears as a superscript throughout the text wherever the source is referenced. The numbered reference list at the end of the document is arranged in order of first citation — not alphabetically, as in APA or MLA. This system keeps the prose clean and readable, which matters in clinical writing where dense methodology sections might otherwise become citation-heavy.
This guide covers every aspect of AMA citation format you need for medical and health sciences writing: the core rules, copy-ready examples for all common source types, the differences between AMA and related styles like Vancouver, and the most common formatting errors that result in manuscript rejection or required corrections. After reading it, run your reference list through an automated reference checker to catch any remaining errors before submission.
Quick Answer: AMA Citation at a Glance
- In-text citations: Superscript numbers ¹ ² ³ in order of first appearance
- Reference list: Numbered in order of first citation (not alphabetical)
- Author format: Surname followed by initials without periods (Smith JM)
- Journal titles: Abbreviated using NLM standard abbreviations, in italics
- DOI format: doi:10.xxxx/xxxxx (no space after colon, no https://)
- Current edition: AMA Manual of Style, 11th edition (2020)
What Is AMA Citation Style?
AMA citation style was developed by the American Medical Association to standardize how medical research is cited across journals, textbooks, and clinical reports. The system is designed for the specific needs of biomedical communication: it allows authors to cite multiple sources efficiently, handles complex technical source types like clinical trial registrations and drug package inserts, and integrates with the DOI system that is now standard across biomedical publishing.
AMA is closely related to the Vancouver style (also called ICMJE style, after the International Committee of Medical Journal Editors). Both use numbered superscript citations in order of appearance and share many formatting conventions. The key differences between AMA and Vancouver are in punctuation, journal title formatting, and specific details for unusual source types. If your target journal specifies "Vancouver style" or "ICMJE style," consult that journal's specific author guidelines, as there can be journal-level variations.
Is AMA 11th edition still current in 2026? Yes. The AMA Manual of Style, 11th edition, published in 2020, remains the current authoritative standard as of 2026. The AMA Style Insider blog and the online edition at oxfordmedicine.com receive periodic clarifications, but the core 11th edition rules are unchanged. When in doubt, check the journal's specific author guidelines, which may specify particular preferences within the AMA framework.
Primary Use
Medical journals, health sciences, nursing, dentistry, pharmacy, and public health research
In-Text Format
Superscript numbers in order of first appearance: Smith et al¹ demonstrated that...
Reference List
Numbered in order of first citation, not alphabetically — entirely different from APA and MLA
AMA Core Formatting Rules
These rules apply across all AMA citations. Understand them once, and applying them to specific source types becomes straightforward.
Rule 1: Author Name Format
Format: Surname followed by initials without periods and without spaces between initials
One author: Smith JM
Multiple authors: Smith JM, Jones AK, Brown RT
Up to 6 authors: List all. For 7 or more, list the first 3 followed by "et al"
Example: Smith JM, Jones AK, Brown RT, et al.
Rule 2: In-Text Citation Format
Format: Superscript Arabic numbers immediately after the relevant text
Single source: Recent research¹ has shown...
Multiple sources: Several studies²⁻⁴ have confirmed...
Non-consecutive: As reported previously¹,³,⁵...
Placement: After punctuation (period, comma) but before a dash; after the author's name if named in text
Example: Jones and Smith¹ demonstrated that...
Rule 3: Journal Title Abbreviations
Required: Abbreviate journal names using NLM (National Library of Medicine) standard abbreviations
Italics: Abbreviated journal titles are in italics
No periods: Do not use periods after abbreviations
New England Journal of Medicine → N Engl J Med
Journal of the American Medical Association → JAMA
The Lancet → Lancet
Annals of Internal Medicine → Ann Intern Med
Rule 4: Volume, Issue, and Page Format
Format: Year;volume(issue):page-range. — note the semicolon after year
Volume: No label, just the number
Issue: In parentheses, immediately after volume
Pages: Use the shortest form that is unambiguous (e.g., 134-138 not 134-8)
Example: 2021;325(14):1432-1440.
Rule 5: DOI Format
AMA format: doi:10.xxxx/xxxxx (lowercase "doi", colon immediately after, no space)
Not a URL: AMA uses the doi: prefix format, not https://doi.org/ (unlike APA 7th edition)
Required: Include the DOI for all journal articles where available
Placement: At the very end of the reference, after the page range
✓ Correct: doi:10.1001/jama.2021.1234
✗ Wrong: https://doi.org/10.1001/jama.2021.1234
✗ Wrong: DOI: 10.1001/jama.2021.1234
AMA Reference Examples by Source Type
The following examples are formatted correctly for AMA 11th edition. Copy and adapt them for your own references, then verify the result.
Journal Article (Most Common)
Format
Example (1–6 authors)
Example (7+ authors, et al)
In-text citation
Book (Entire Volume)
Format
Example
Key rules
- • Book title in italics, title case
- • "ed." or "eds." for editor(s) after the name, before the title
- • Publisher name only — no city of publication (unlike Chicago)
- • Semicolon between publisher and year
Chapter in an Edited Book
Format
Example
Website / Online Resource
Format
Example (organization as author)
Key rules
- • Access date is required for websites (content may change)
- • Include both the publication/update date and the access date
- • URL at the end without a period after it
Clinical Trial Registration
Format
Example
Government Report or Agency Publication
Format
Example
Newspaper Article
Format (print)
Format (online)
Example
Thesis or Dissertation
Format
Example
In-Text Citation Rules in Detail
AMA's superscript citation system has specific placement rules that differ from parenthetical styles like APA and MLA.
Placement Relative to Punctuation
Superscript numbers are placed after punctuation marks (commas, periods, colons, semicolons) but before dashes. They are placed after the author's name if the author is named in the sentence.
Citing Multiple Sources
When citing multiple sources at the same point, list the numbers in numerical order, separated by commas for non-consecutive numbers or by an en-dash for a range.
Reusing Citation Numbers
Once a source has been assigned a number, that same number is used every time the source is cited again in the text. You do not assign a new number for subsequent citations of the same source.
Most Common AMA Citation Errors
These are the errors that appear most often in AMA-formatted manuscripts and are most likely to trigger a return from journal editorial staff.
1. Using Alphabetical Order Instead of Citational Order
This is the single most frequent AMA error, particularly among researchers who regularly use APA or Harvard style. In AMA, the reference list is numbered in the order sources are first cited in the text — if Smith (2021) is cited first in your introduction, it is reference 1 regardless of alphabetical position.
Common mistake:
Arranging references A–Z by author surname (APA habit) when AMA requires order of first citation.
2. Incorrect DOI Format
AMA uses the doi: prefix format, not the https://doi.org/ URL format that APA 7th edition requires. Many researchers who work across styles apply the wrong DOI format. Additionally, some omit the DOI entirely when it is available — AMA requires DOI inclusion for all journal articles where a DOI exists.
✓ AMA correct: doi:10.1001/jama.2021.1234
✗ Wrong (APA format): https://doi.org/10.1001/jama.2021.1234
✗ Wrong: DOI: 10.1001/jama.2021.1234 (capital D, space after colon)
3. Periods After Author Initials
AMA does not use periods after initials. "Smith J.M." is incorrect in AMA — the correct format is "Smith JM". This error often appears in references imported from databases that add periods to initials.
✓ Correct: Smith JM, Jones AK
✗ Wrong: Smith, J.M., Jones, A.K.
4. Full Journal Name Instead of NLM Abbreviation
AMA requires NLM-standard journal abbreviations. Using the full journal name, a non-standard abbreviation, or an abbreviation with periods (e.g., "J.A.M.A.") is incorrect. Look up abbreviations in the NLM catalog or PubMed.
5. Superscript Numbers in Wrong Position
Placing superscript numbers before punctuation rather than after is a common error. The number must follow the comma or period, not precede it.
✓ Correct: This effect has been reported.¹
✗ Wrong: This effect has been reported¹.
6. Missing "et al" for 7+ Authors
When a paper has 7 or more authors, AMA requires listing only the first 3, followed by "et al" (no period, no italics). Listing all authors for papers with many co-investigators, or applying a different threshold (e.g., 6 or more as in older guidelines), is incorrect.
AMA vs Vancouver vs APA: Key Differences
Medical researchers frequently work across journals with different style requirements. This table highlights the most important differences between AMA, Vancouver, and APA — the three styles most commonly encountered in health and social sciences.
| Feature | AMA 11th | Vancouver / ICMJE | APA 7th |
|---|---|---|---|
| In-text format | Superscript numbers | Superscript or bracketed numbers | Author-date (Smith, 2021) |
| Reference order | Order of first citation | Order of first citation | Alphabetical by author |
| Author initials | No periods (Smith JM) | No periods (Smith JM) | No periods (Smith, J. M.) |
| DOI format | doi:10.xxxx/xxxx | Varies by journal | https://doi.org/10.xxxx/xxxx |
| Et al threshold | 7+ authors (list first 3) | Varies (often 6+) | 3+ authors in-text; 21+ in reference list |
| Journal abbreviation | NLM standard, no periods | NLM standard, no periods | Full journal name |
| Publisher location (books) | Not required | Often included | Not required |
Best Practices for AMA Citation
1. Configure Your Reference Manager for AMA Output
Zotero, Mendeley, and EndNote all include AMA citation styles. Configure the output style before writing and insert citations using the plugin as you draft. This eliminates manual number tracking during revisions. After any major edit, re-run a full check to confirm numbering remains sequential and matches in-text citation numbers.
2. Verify Metadata at Point of Import
When importing references from PubMed, CrossRef, or a database, verify the imported metadata immediately against the paper's title page. Author initials, publication year, and journal abbreviation are frequently wrong in database exports. A quick check at import prevents errors from propagating through your entire manuscript.
3. Check Against the Target Journal's Recent Issues
Before submission, pull 2–3 recent research articles from your target journal and compare their reference formatting with yours. Journals using AMA may have specific house preferences — some require article titles, others omit them; DOI format preferences can vary. Published articles from that journal are the most authoritative style guide available.
4. Run an Automated Reference Check Before Submission
An automated reference checker configured for AMA style will catch formatting errors, missing DOIs, incorrect journal abbreviations, and sequence numbering problems across your entire reference list in seconds. Run it after the final draft and again after any corrections.
Frequently Asked Questions
Do AMA citations include article titles for journal articles?
Yes. Unlike Vancouver style (which sometimes omits article titles), AMA 11th edition includes the article title in journal article references. The title appears in sentence case — only the first word and proper nouns are capitalised. This differs from book titles, which use title case.
What does "et al" look like in AMA format?
In AMA, "et al" appears without a period after "al" and without italics. It is used in the reference list when a paper has 7 or more authors (list the first 3, then "et al"). In in-text citations, you may also write "Smith et al" (no superscript before et al itself) followed by the superscript number.
What is the difference between AMA and AMA style for student papers?
The core citation rules are the same. Student papers in AMA format may differ in manuscript formatting requirements — running heads, abstract structure, and section headings — depending on the institutional guidelines. Always check your course or programme handbook alongside the AMA Manual of Style for any student-specific requirements.
How do I cite a drug package insert in AMA format?
Drug package inserts are cited as manufacturer documents. The general format is: Drug Name [package insert]. Manufacturer; Year. Example:
Conclusion: Mastering AMA Citation Format
AMA citation style is designed for efficiency and clarity in medical and health sciences communication. Once you understand its core logic — numbered superscripts in order of appearance, NLM journal abbreviations, the doi: prefix format, and author names without periods — applying it consistently becomes straightforward.
The most important thing to remember is that AMA's numbered system requires careful management during revision. Every time you add, remove, or reorder citations, the sequence must be rechecked. A reference management tool configured for AMA output handles this automatically; a final automated citation check catches anything that slips through.
Always verify your reference list against your target journal's author guidelines and a recent published issue before submission. The extra ten minutes invested in pre-submission verification can save weeks of revision delays.
Verify Your AMA References Before Submission
Upload your manuscript and check every AMA citation for format compliance, missing DOIs, and numbering errors — before your editor does.
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