What Does Preprint Mean in Citation? Style Guide

In a citation, “preprint” is a status marker: it tells the reader that the work is a publicly posted manuscript that has not yet completed formal peer review. When you see “[Preprint]” attached to a bioRxiv or medRxiv reference, the correct response is to treat the findings as provisional and to check whether a peer-reviewed version now exists before you rely on it. A preprint is a complete draft of a research paper, posted to an open server such as bioRxiv, medRxiv or arXiv, that is publicly available and citable by DOI before — and sometimes instead of — journal publication.

This guide sets out exactly how to format a what does preprint mean in citation answer into a working reference: the DOI, the version number, and the “not peer reviewed” disclosure that most journals and funders now expect, across APA, Vancouver and the common journal house-style variants.

Contents

• What does “preprint” mean in a citation?
• How do you cite a bioRxiv or medRxiv preprint?
• How do you cite a bioRxiv preprint in EndNote?
• What must a preprint citation disclose?
• Common questions about citing preprints

What does “preprint” mean in a citation?

A preprint citation flags that the cited work has not been certified by peer review at the time of citing. Most reference styles handle this with a bracketed qualifier — “[Preprint]” — placed after the title, plus a DOI that resolves to the version posted on the server.

The distinction matters because a preprint can change between versions. bioRxiv and medRxiv both append a version suffix to the DOI landing page (v1, v2, v3), and a citation that omits the version number cannot be traced back to the exact text a reader analysed. The NIH Preprint Pilot, which indexes preprint records with citation metadata in PubMed Central, treats “certification by peer review” as the defining line between a preprint and an accepted manuscript.

How do you cite a bioRxiv or medRxiv preprint?

Every major style requires three elements beyond a normal journal citation: the preprint server name, a “[Preprint]” or “not peer reviewed” marker, and the DOI (with version number where the style permits it). The table below gives working templates for the styles authors are most often asked to use.

Three formatting rules hold across all four styles above:

• Always cite the version you actually read. Append the version suffix from the DOI landing page (for example, v2) if the journal’s instructions for authors allow it.
• Never drop the preprint marker. Removing “[Preprint]” or “not peer reviewed” from the reference makes the source indistinguishable from a certified journal article, which most editorial policies treat as a disclosure failure rather than a formatting slip.
• Prefer the published version once one exists. The APA Style guidelines state that authors should cite the final published article in preference to the preprint whenever both are available.

How do you cite a bioRxiv preprint in EndNote?

EndNote has no universally available native “Preprint” reference type in every library version, so the reliable workaround is to use the Electronic Article or Unpublished Work reference type and populate it manually:

1. Create a new reference and set the type to “Electronic Article” (or “Unpublished Work” if your library lacks that type).
2. Enter the preprint server as the Journal or Publisher field (e.g. “bioRxiv” or “medRxiv”).
3. Paste the full DOI, including the version suffix, into the DOI field.
4. Add “Preprint, not peer reviewed” into the Notes or Type of Work field so it renders in the output style.
5. If your output style does not display the Notes field by default, edit the output style’s bibliography template to insert it after the title — otherwise the preprint status will silently disappear from the final reference list.

This matters because EndNote output styles are typically built around journal-article fields; without the manual notes step, a bioRxiv or medRxiv record will format identically to a peer-reviewed article, which is the exact disclosure gap that journal editorial policies are designed to prevent.

What must a preprint citation disclose?

Three elements recur across every editorial policy that addresses preprints: the DOI, the version number, and an explicit statement that the work is not peer reviewed.

• DOI. Both bioRxiv and medRxiv register a Crossref DOI for every posted version, so there is no reason to cite a preprint without one.
• Version number. Because preprints can be revised after posting, citing only the server name and DOI without the version risks referencing content that has since changed.
• “Not peer reviewed” disclosure. The NIH issued formal reporting guidance in 2017 requiring that citations of preprints and other interim research products indicate the preprint status, the DOI, the document version and the date it was accessed. Several major publishers, including Nature Research, now require the same disclosure directly in the reference text.

Despite this, preprint citation policy remains inconsistent across the scholarly record. An analysis of 171 academic journals across disciplines — cited by ASAPbio and published as a bioRxiv preprint itself (Klebel et al., 2020, DOI: 10.1101/2020.01.24.918995) — found that 57.3% had no publicly stated policy on whether preprints could be cited at all, with life-sciences and earth-sciences journals the most likely to have a defined policy. Authors should check a target journal’s instructions for authors before submission rather than assume a default position.

Common questions about citing preprints

Is a preprint a reliable source to cite?

A preprint can be a legitimate, citable source, but it has not passed peer review, so its claims are provisional. Readers should check for author affiliations, data availability, and any subsequent published version before treating its findings as settled.

Can I use a preprint as a reference in a journal article?

Yes. A majority of life-sciences journals now permit preprints in the reference list, provided the citation clearly marks the source as a preprint. Always confirm the specific journal’s policy in its instructions for authors first.

How do I know if an article I’m citing is a preprint?

Check the DOI prefix and server name — bioRxiv and medRxiv DOIs begin with 10.1101 — and look for an explicit “preprint” or “not peer reviewed” label on the source page itself, since this is the only reliable indicator of certification status.

Should I cite the preprint or wait for the published version?

Cite whichever version you actually used, but if a peer-reviewed version has since been published, update the reference to point to it. Style guides including APA explicitly recommend citing the final published article over the preprint once one exists.

Implications for authors, editors and administrators

Preprint citation is no longer a fringe practice: it is now embedded in NIH reporting guidance, journal house styles, and reference-manager workflows. Research-administration teams supporting grant reporting, tenure files, and systematic reviews should treat the DOI-plus-version-plus-disclosure format as a compliance minimum, not a stylistic nicety, because omitting the “not peer reviewed” marker can misrepresent the certification status of cited evidence. As more funders and publishers formalise preprint policy, the citation itself — not just the underlying manuscript — becomes part of the scholarly record’s audit trail.

For definitions of related terms used across research-administration standards, see the CASRAI Dictionary, and for guidance on how contributions and authorship are documented alongside citations, see CASRAI’s authorship resources.