IRB Number (IRB ID)

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.

Why the research administration office tracks this number beyond citation

A study’s IRB number is not just a citation formality — it is the key a sponsored-programs or human-subjects protection office uses to reconcile three things that have to stay consistent for the life of the award: the protocol under active IRB oversight, the consent language participants actually signed, and the award terms a funder is monitoring. A pre-award or post-award auditor checking human-subjects compliance on a federal award typically verifies that the number on the Notice of Award, the number on the current IRB approval letter, and the number in the consent form on file all match — a mismatch (common after an amendment that a study team forgot to route through the sponsored-programs office) is one of the more frequent findings in a human-subjects compliance review, even when the underlying research conduct was never actually out of compliance.

The number also changes hands, structurally, once a study becomes a single IRB (sIRB) arrangement. Since 2020, 45 CFR 46.114 has generally required that federally funded cooperative (multi-site) human-subjects research use a single IRB of record for the portions of the study conducted in the United States, and NIH’s parallel single-IRB policy has applied to NIH-funded multi-site studies since 2018. In that arrangement, the reviewing IRB assigns the protocol number that governs the study, while each relying institution typically still keeps its own local tracking number — via a reliance agreement (commonly executed through the SMART IRB platform) — for its own institutional recordkeeping and its own award file, even though it is not the number of record for federal human-subjects reporting. Confusing “our local tracking number” with “the reviewing IRB’s protocol number” on a reliance study is a distinct, newer version of the three-number mix-up above, and it is the research administration office — not the study team — that is usually positioned to know which number a given federal reporting field actually wants.

Checking this against the current guidance

Which number belongs in a specific federal report or reliance record depends on whether the study runs under a single-institution IRB or a multi-site reliance arrangement, and on which agency’s reporting template is asking — a distinction this page states in general terms but cannot resolve for a specific award.

Ask CASRAI: When our institution relies on an external single IRB of record for a multi-site NIH-funded study under 45 CFR 46.114, does the relying institution still need its own IRB tracking number for local recordkeeping, or does the federal reporting obligation attach only to the reviewing IRB’s protocol number?

It searches CASRAI’s indexed corpus of research-administration guidance and cites the passage behind each claim, so you can open the source and check it rather than take its word — and it says so when the corpus does not cover something instead of guessing. Two questions a day are free while you are signed out, no account and no card. Everything CASRAI publishes stays free to read.

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.

Which IRB number applies when a study uses a single IRB of record across multiple sites?

The reviewing IRB’s protocol number is the number of record for federal human-subjects reporting on a single-IRB (sIRB) study under 45 CFR 46.114 or NIH’s parallel policy. A relying institution typically still maintains its own local tracking number through its reliance agreement for its own award file, but that local number is not a substitute for the reviewing IRB’s protocol number on federal reports.