A journal website says its articles are in PubMed. That can mean MEDLINE selection, a PMC agreement, or a few deposited papers. Here is how to tell which.
PubMed, PMC, and MEDLINE are three different things
NLM describes PubMed as a database of citations and abstracts, not full text, drawing on MEDLINE, PubMed Central (PMC), and the NCBI Bookshelf.
| Database | What it is | How content gets in | What a listing tells you |
|---|---|---|---|
| PubMed | Free database of citations and abstracts | Through MEDLINE, PMC, or Bookshelf | That a citation exists |
| MEDLINE | Largest part of PubMed, indexed with MeSH terms | NLM selects whole journals after a scientific and editorial quality review | That NLM selected the journal |
| PMC | Free full-text archive | Journals accepted under participation agreements, plus individual articles deposited under funder policies | That full text is archived, by agreement or article by article |
The decision rule: "in PubMed" is the weakest claim a journal can make, and "currently indexed for MEDLINE" is the most specific. A PMC claim sits between them and needs its own check.
Why "indexed in PubMed" can mean very little
A citation can reach PubMed without the journal ever being selected for MEDLINE or joining PMC. PubMed's help pages note that it includes U.S. government-funded research published in journals not indexed for MEDLINE, typically through individual articles deposited in PMC to meet funder policies. So a journal can truthfully say its articles "appear in PubMed" when that describes a handful of papers.
The reverse trap trips up authors checking a real MEDLINE journal. NLM's policies say indexing for a newly selected journal typically begins with the current year or volume, so earlier articles usually stay in PubMed without MEDLINE indexing. A journal selected two years ago can therefore have far more unindexed citations than indexed ones and still be a genuine MEDLINE title. The exception is a young journal: if it is within its first three volumes when accepted, indexing may begin with volume 1. This decides which citations you may count in the PubMed test below.
Our guide to spotting predatory journals lists misleading indexing claims as a red flag. The steps below are how you test one.
The seven-step check
- Copy the ISSN from the journal's website. No ISSN on the site is itself a question to ask.
- Search the NLM Catalog by ISSN. Start from the Journals referenced in the NCBI Databases page.
- Read the Current Indexing Status and In fields. Covered in the next section.
- Confirm it is the same journal. See the identity check below.
- Check the PMC Journal List by NLM ID. Covered after the catalog record.
- Test the claim in PubMed. The search strings are below.
- Record what you found and when. The closing checklist lists the fields.
Reading the NLM Catalog record
Two fields in the record carry the answer. Current Indexing Status reads either "Currently indexed for MEDLINE" or "Not currently indexed for MEDLINE." In lists where the journal is covered, with volume and date ranges for MEDLINE and PubMed.
| What the record shows | What it means |
|---|---|
| Currently indexed, with an open-ended MEDLINE range | Selected and indexed now; articles before the start date are not in MEDLINE |
| Not currently indexed, with a closed MEDLINE range | Indexed for that period only; find out why before relying on it |
| Not currently indexed, no MEDLINE line, PubMed and PMC listed | Citations reach PubMed through PMC; not a MEDLINE journal |
| No MEDLINE or PMC line at all | Neither MEDLINE coverage nor PMC participation recorded for this title |
A closed range can mean the journal changed title, ceased, or stopped being indexed. The Continues and Continued By fields show whether coverage moved to another record, often with a new ISSN.
The identity check deserves more care than it usually gets. A look-alike site can copy a real journal's title and even its ISSN, so the Electronic Links field is the one that distinguishes them: it should point at the domain that invited your manuscript. Record links can be out of date, so treat a mismatch as a reason to investigate, not proof of fraud. Our guide to choosing a journal without getting scammed covers the wider checks.
A shortcut from the NLM Catalog search box: 1234-5678[issn] AND currentlyindexed, with the real ISSN in place of the placeholder, returns the record only if the journal is currently indexed for MEDLINE. Use journalspmc instead to test for current PMC journals.
Reading the PMC Journal List
Search the PMC Journal List with the NLM Unique ID from the NLM Catalog record. PMC's user guide says the search box looks for words in a journal's title or the NLM Unique ID, so an ISSN will not find it. Two fields answer the question:
- Agreement Status. Active means the journal is currently depositing. No longer participating, No longer published, and Predecessor title mean it is not depositing under that record.
- Agreement to Deposit. All articles is a Full Participation agreement. NIH-funded articles is an NIH Portfolio agreement, so the journal's other papers may not be in PMC.
If the journal is not on the list but some of its articles are in PMC, those are individual deposits; PMC notes that such journals are not searchable in the Journal List.
If an NIH grant supports your work, the agreement tells you whether the journal deposits the final published article for you. If there is none, expect to deposit your accepted manuscript through the NIH Manuscript Submission (NIHMS) system. Our explainer on article versions sets out what counts as an accepted manuscript.
Testing the claim in PubMed
Search PubMed with the NLM Title Abbreviation from the NLM Catalog record, in quotes with the journal tag, as in "J Example Med"[ta]. PubMed's help recommends the title or abbreviation over the ISSN for complete retrieval, because older citations may lack one. Then run it twice more:
- add
AND medline[sb]to see only citations indexed for MEDLINE - add
AND pubmednotmedline[sb], another citation status subset listed in PubMed's help, and compare the two counts
Judge only the citations published on or after the MEDLINE start date in the In field. As noted above, that date usually falls in the year of selection, or at volume 1 for a journal accepted within its first three volumes. Add AND 2024:2026[dp] or whatever range starts at that date, or a run of older years will make a genuine claim look false. Then read the results:
- A biomedical journal claims MEDLINE, but citations published since the start date are mostly PubMed-not-MEDLINE. The claim does not hold.
- Most citations are PubMed-not-MEDLINE, but they all predate the start date. That is the normal pattern for a recently selected journal, not a problem.
- MEDLINE citations stop at a past year. Go back to the In field dates in the NLM Catalog record.
- Only the last few weeks are missing from the MEDLINE set. Those are probably still in process; leave them out and judge on the rest of the range.
- A journal with no MEDLINE coverage and no PMC agreement has scattered records. They most likely reflect individual PMC deposits, not a decision about the journal.
Indexing status can change
Under NLM's MEDLINE policies, a journal can be reevaluated over unaddressed or systemic article problems, verifiable quality concerns, or a significant change such as a new publisher. During a reevaluation NLM holds new content, and if the journal fails, indexing stops and the held articles are not indexed. So a title can be "currently indexed" on a list you saved last year and not today.
Authors should check at the point of submission rather than trusting an older note. Research offices should store the NLM ID and ISSN alongside each title in any approved-journal list and re-run the check at every review: a title change usually appears as a new NLM Catalog record linked to the old one, which a title-only list will miss.
What to write down
Keep the answers, not just the verdict, so a co-author or research office can re-check without repeating the work:
- NLM Unique ID, and the ISSN you searched on
- Current Indexing Status, copied verbatim from the record
- MEDLINE start date from the In field, and whether the range is open-ended
- PMC Agreement Status and Agreement to Deposit, if PMC matters to your funder
- The medline[sb] count for the range since the start date, with the date you ran it
- Any mismatch between the record's electronic links and the submission site
What indexing does and does not tell you
A current MEDLINE status tells you NLM reviewed the journal's scientific and editorial quality and still indexes it. It does not tell you whether the journal suits your paper, and the PMC disclaimer states that the presence of an article in NLM's databases does not imply NLM endorses its contents. Run these checks alongside the scope and fit questions, not instead of them.
Directive Publications sets out its author resources and publishing standards, and when you are ready, you can submit your manuscript.
Frequently asked questions
What is the difference between PubMed and MEDLINE?
PubMed is the free NLM database of citations and abstracts. MEDLINE is its largest component, made up mainly of citations from journals NLM has selected after a scientific and editorial quality review, indexed with MeSH terms. PubMed also holds citations from PubMed Central and the NCBI Bookshelf, so a record in PubMed does not by itself mean MEDLINE indexing.
Does being in PMC mean a journal is indexed in MEDLINE?
No. PMC is a full-text archive with its own participation agreements, and a journal can deposit in PMC while its NLM Catalog record reads Not currently indexed for MEDLINE. PMC also holds individual articles deposited to meet funder policies from journals that are not on the PMC Journal List. Check the MEDLINE status separately in the NLM Catalog.
How do I use the NLM Catalog to check a journal's indexing status?
Open the NLM Catalog search page for journals referenced in the NCBI databases and search by the journal's ISSN rather than its title. In the record, read the Current Indexing Status field, then the In field, which gives MEDLINE and PubMed coverage dates and shows PMC where it applies. Confirm that the ISSN, publisher and web address match the journal you are actually considering.
Why do some articles appear in PubMed when the journal is not MEDLINE-indexed?
Citations reach PubMed by routes other than MEDLINE. The journal may deposit its content in PMC, or individual articles may have been deposited in PMC to meet a funder's policy, and those articles are cited in PubMed. MEDLINE journals also have PubMed citations that are not indexed for MEDLINE, such as articles published before the journal's indexing start date.
Can a journal lose its MEDLINE indexing?
Yes. NLM can reevaluate a MEDLINE journal and stop indexing it, and it can also stop indexing titles that no longer meet its technical requirements. You will see it in the NLM Catalog record, where the status changes to Not currently indexed for MEDLINE and the MEDLINE range in the In field closes. A list saved months ago will not show the change.