Direct comparison
Unanticipated Problem vs Adverse Event
AE/SAE reporting runs to the sponsor on a fixed FDA clock. UPIRSO reporting runs to the IRB only if it passes OHRP's three-part test. Different tracks.
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How do Unanticipated Problem (UPIRSO), Adverse Event / SAE compare side by side?
The table below compares Unanticipated Problem (UPIRSO), Adverse Event / SAE across 8 procurement-relevant dimensions, from governing regulation through recipient of the report.
Side-by-side comparison
| Dimension | Unanticipated Problem (UPIRSO) | Adverse Event / SAE |
|---|---|---|
| Governing regulation | 21 CFR 56.108(b) — IRB written procedures for prompt reporting | 21 CFR Part 312 sponsor pharmacovigilance framework; 21 CFR 312.64(b) investigator-to-sponsor reporting |
| Who makes the reportability determination | The IRB (directly, its chair, or a delegated reviewer) — investigator makes the initial call, IRB decides | The study sponsor, evaluating for expectedness and causality across all sites |
| The test applied | OHRP's three-part test: unexpected, AND related or possibly related, AND suggestive of greater risk — all three required | Any untoward medical occurrence, tracked regardless of causality; escalates to SUSAR if unexpected and serious |
| Reporting timeline | "Prompt" — no fixed federal day-count; each IRB sets its own window in written procedures, typically scaled to severity | Investigator to sponsor: immediate. Sponsor to FDA (SUSAR): 7 calendar days if fatal/life-threatening, 15 for others, from sponsor awareness (21 CFR 312.32) |
| Scope beyond medical events | Yes — a confidentiality breach, consent-process failure, or device risk-profile change can be a UPIRSO with no associated medical adverse event | No — this track is specific to medical occurrences in participants |
| An expected, consent-disclosed SAE | Not reportable as a UPIRSO — fails the "unexpected" prong even though it's serious | Routinely reportable and tracked through ordinary SAE monitoring |
| A non-serious event revealing a new risk | Can be a reportable UPIRSO if it meets all three test conditions | Would likely never reach SUSAR reporting thresholds on its own |
| Recipient of the report | IRB, appropriate institutional officials, and FDA where applicable; OHRP for FWA-covered research meeting its most-serious-incident criteria | Study sponsor first, then FDA (or EudraVigilance) if the event qualifies as a SUSAR |
Common questions
Common questions about Unanticipated Problem (UPIRSO) vs Adverse Event / SAE
Is every serious adverse event reportable to the IRB as an unanticipated problem?
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No. A serious adverse event that's expected — already disclosed in the consent form and occurring at the anticipated rate — fails the "unexpected" prong of OHRP's three-part test, so it isn't a reportable UPIRSO, even though it will typically still be tracked and reported through the sponsor/FDA SAE/SUSAR pipeline.
What's the actual difference between reporting an AE to the sponsor and reporting it to the IRB as a UPIRSO?
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Sponsor/FDA reporting is aggregate drug or device safety monitoring across every trial site, governed by 21 CFR Part 312 with fixed federal timelines for serious unexpected reactions. IRB/UPIRSO reporting is a separate, local-institution process under 21 CFR 56.108(b), asking whether a specific event changes the study's known risk profile at the local level and whether the IRB needs to act — amend the protocol, revise consent, or suspend enrollment.
Does an unexpected adverse event automatically have to be reported to the IRB as a UPIRSO?
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No — it also has to be judged related (or possibly related) to study participation and to suggest greater risk than previously known. An unexpected event clearly caused by something unrelated to the study, or one that doesn't change the risk calculus, fails the test even though the "unexpected" prong is met.
How quickly does a UPIRSO have to be reported, compared to a SUSAR?
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A SUSAR has a fixed federal clock: 7 calendar days for fatal or life-threatening events, 15 for others, measured from the sponsor's awareness, under 21 CFR 312.32. A UPIRSO has no equivalent fixed federal day-count — 21 CFR 56.108(b) requires only "prompt" reporting, and each IRB defines its own binding window in its written procedures.
Can an event be both a SUSAR and a UPIRSO?
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Yes. Nothing prevents an event from qualifying on both tracks simultaneously — an unexpected, related, greater-risk event that's also serious can trigger sponsor-to-FDA SUSAR reporting on its own federal clock and IRB UPIRSO reporting on the institution's own clock, at the same time, evaluated independently by two different reviewers against two different tests.
Going deeper
