IRB Number: What It Is and Where to Find Yours

IRB Number (IRB ID)

The unique identifier an Institutional Review Board assigns to a single approved research protocol at the time of initial submission, used to track and reference that specific study throughout its review lifecycle (approval, amendment, continuing review, closure) and to cite in manuscripts, consent forms, and funder reports — distinct from the institution's OHRP IRB Registration Number (identifies the review board itself) or Federalwide Assurance (FWA) number (identifies the institution as a whole).

ByCASRAI Editorial Board

· Last updated 15 Aug 2026

Ask about IRB Number (IRB ID)

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Worked examples

Is an instance

A manuscript's methods section states: "The study protocol was approved by the Institution X IRB (Protocol #2024-118) prior to enrollment" — the number cited is the study-specific IRB/protocol number, not the institution's OHRP registration number or FWA number.

Is an instance

A protocol keeps the same IRB number across its full lifecycle — initial approval, subsequent amendments, and annual continuing-review renewals — even though its approval status and expiration date change with each cycle.

Looks similar, but isn't

Not an instance

An institution's Federalwide Assurance number (e.g., an FWA-prefixed number issued by OHRP) identifies the institution's overall assurance to comply with the Common Rule, not a specific study — citing it as "the IRB number" for a particular protocol is a common but incorrect substitution.

Not an instance

An IRB Registration Number issued by OHRP identifies the review board itself as an entity registered to conduct human-subjects review; it does not change per study and is not what a journal or funder is asking for when it requests the approval number for a specific protocol.

An IRB number (also called an IRB ID, IRB approval number, or protocol number) is the unique identifier an Institutional Review Board assigns to one specific approved research protocol. It is what a journal, funder, or institutional system is asking for when it requests “your IRB approval number” in a manuscript submission, consent form, or grant application — and it is a different thing from two other, institution-level identifiers that also get called “IRB numbers” informally.

Three different numbers, easy to confuse

IRB number / protocol number (this term) — assigned by an IRB to a single protocol when that protocol is first submitted for review. It stays with the study for its lifecycle (initial approval, amendments, continuing review, closure) and is the number a manuscript’s ethics-approval statement or a consent form should cite.
IRB Registration Number — assigned once by the HHS Office for Human Research Protections (OHRP) to a specific review board itself, not to any study it reviews. It identifies the committee/panel as an entity registered to conduct human-subjects review.
Federalwide Assurance (FWA) number — assigned once by OHRP to the institution as a whole, covering its overall commitment to comply with the Common Rule. An institution can operate under one FWA while its designated IRB(s) hold their own, separate registration number(s); one IRB can also be designated under multiple institutions’ FWAs, which is the basis for reliance/sIRB arrangements.

All three can appear on the same approval letter, which is why the study-specific protocol number is easy to mistake for one of the two institution-level identifiers — or vice versa.

Where to find it and how to cite it

The protocol-specific IRB number appears on the IRB’s approval/determination letter for that study, and typically also in the electronic IRB (eIRB) submission system record the research office maintains for that protocol. When a journal’s ethics-statement requirement or a funder’s reporting template asks for “the IRB approval number,” it is this study-specific number that belongs in the manuscript or report — not the institution’s FWA number and not the reviewing board’s OHRP registration number, neither of which changes per study and neither of which identifies which protocol was reviewed.

References

HHS OHRP, “IRB Registration” and “IRB Organizations (IORGs)”, hhs.gov/ohrp
Common Rule, 45 CFR 46 (institutional/IRB assurance and registration provisions)

Frequently Asked Questions

What is the difference between an IRB number and an IRB Registration Number?

An IRB number (or protocol number) identifies one specific research protocol and is assigned by the IRB when that study is first submitted for review. An IRB Registration Number is a different identifier, assigned once by the HHS Office for Human Research Protections (OHRP) to the review board itself, not to any individual study it reviews.

Is an IRB number the same as a Federalwide Assurance (FWA) number?

No. The Federalwide Assurance (FWA) number is assigned once by OHRP to an institution as a whole, covering its overall commitment to comply with the Common Rule. It does not identify an individual study, so it should not be cited in place of a study’s own IRB/protocol number.

Where can I find my study’s IRB number?

It appears on the IRB’s approval or determination letter for that specific study, and is typically also recorded in the electronic IRB (eIRB) submission system that the institution’s research office maintains for that protocol.

Does the IRB number change when a protocol is amended or renewed?

No. The IRB number stays with the study for its full lifecycle, covering initial approval, amendments, continuing review, and closure, even though the approval status and expiration date change with each cycle.

Is there a public database where I can look up an IRB number?

No. A study’s IRB/protocol number is not published in a public registry; it is issued and recorded by the reviewing institution and appears on that study’s own approval letter or eIRB record, so retrieving it means checking with the study team or the institution’s research office rather than searching online.

Use in your systems

JATS XML <role> element

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Schema.org DefinedTerm (JSON-LD)

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