There is no single SAE deadline. An investigator reports to the sponsor quickly, the sponsor reports suspected unexpected serious reactions to regulators on 7- and 15-day clocks, and the regions differ on who starts the clock and who receives the report. This guide compares them, flags where the UK rules changed in 2026, and links to a calculator for the dates.
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| Fatal or life-threatening | Other qualifying | |
|---|---|---|
| Investigator to sponsor (SAE) | Immediately / within 24 hours | Immediately / within 24 hours |
| FDA IND safety report (21 CFR 312.32) | 7 calendar days | 15 calendar days |
| EU CTR SUSAR (Reg 536/2014) | 7 days | 15 days |
| ICH E2A | 7 days, complete report 8 days later | 15 days |
| UK MHRA (CTIMPs, from 28 April 2026) | 7 days per secondary sources | Check MHRA guidance |
SAE reporting timelines in brief
Who reports what
A serious adverse event is any untoward medical occurrence that results in death, is life-threatening, requires hospitalisation or prolongs it, causes persistent or significant disability, or is a congenital anomaly, or that is otherwise medically important. Whether an event is serious is about the outcome, not about how severe it feels. If you are unsure which side of the line an event falls on, the serious adverse event decision tree walks through it.
The investigator must tell the sponsor about every serious adverse event, except those the protocol says need not be reported immediately. Under the EU Clinical Trials Regulation the investigator reports without undue delay and no later than 24 hours after becoming aware, and US rules for investigators call for immediate reporting to the sponsor. Your protocol will usually state the exact window and the form.
The sponsor then does the causality and expectedness assessment, and decides whether the event is a suspected unexpected serious adverse reaction. Only those events go to regulators on the expedited clock, together with certain other safety findings under US rules. Everything else is collected and reported in aggregate, for example in annual safety reports. The SUSAR reporting software page covers the sponsor-side workflow.
Region by region
All periods are calendar days. Wording is paraphrased. The UK row reflects secondary sources and a regulatory change in 2026, so confirm it before relying on it.
| Authority | Fatal or life-threatening | Other qualifying | Clock starts | Recipient |
|---|---|---|---|---|
| Investigator to sponsor | No later than 24 hours (EU); immediately (US) | Same, unless the protocol says otherwise | Investigator becomes aware | Sponsor |
| FDA (21 CFR 312.32) | As soon as possible, no later than 7 calendar days | As soon as possible, no later than 15 calendar days | Sponsor initial receipt (7-day); determination that it qualifies (15-day) | FDA, and investigators |
| EU CTR (Reg 536/2014, Art 42) | As soon as possible, no later than 7 days | No later than 15 days | Sponsor becomes aware | EudraVigilance via the EU system |
| ICH E2A | 7 days, then complete report within 8 more days | 15 days | First knowledge that a case qualifies | Per regional authority |
| UK MHRA (CTIMPs) | 7 days from first awareness, per an archived Clinical Trials Toolkit summary | The period in MHRA guidance or protocol; verify | Sponsor first aware | MHRA only (from 28 April 2026) |
Health Canada, Japan, China, Australia, device vigilance and many national regimes have their own rules and are not covered here. Where a study falls under more than one regime, meet each, and the earlier date wins.
UK update
The Medicines for Human Use (Clinical Trials) (Amendment) Regulations 2025 introduced changes to UK clinical trial safety reporting. According to the Health Research Authority, from 28 April 2026 the safety reporting requirements for clinical trials of investigational medicinal products change in line with those regulations. One practical effect: SUSARs and annual safety reports for all CTIMPs, whether or not they used combined review, are reported only to the MHRA. Before that date, trials outside combined review also sent SUSARs to the research ethics committee.
The HRA also says the revised rules apply to trials approved before and after the date, and that a sponsor of an earlier-approved trial may ask the MHRA to continue temporarily under the previous safety reporting requirements. MHRA revised its safety guidance with effect from 1 October 2025, according to a secondary source. The detailed timeframes sit in MHRA guidance rather than in the HRA page. For the period for non-fatal reactions and for the exact clock start, read the current MHRA text, because we have not confirmed it from the primary document.
If you run a UK trial, check three things: the current MHRA safety reporting guidance, the safety section of your approved protocol and whether your trial elected to continue under the previous rules.
Add the adverse event and SAE forms in the free sandbox, enter a test event and follow it through. Every feature, no credit card, no time limit.
Why clock starts matter
Most missed deadlines are not caused by slow paperwork. They are caused by disagreement about when the clock started. A site might report on a Friday, the sponsor's safety desk might open it on Monday, the medical reviewer might confirm expectedness on Wednesday. Under a rule that counts from sponsor receipt, the clock started on Friday. Under one that counts from determination that the case qualifies, it started on Wednesday. Under an EU-style rule that counts from awareness, the question is when the sponsor, or someone the sponsor has delegated to, first knew.
The practical remedy is to define each date in the safety management plan and record it in the case. Capture the date the site became aware, the date the sponsor received the report, the date of the causality and expectedness assessment, and the date each regulator submission was made. Then the compliance check is arithmetic. The SAE reporting deadline calculator computes the due dates under the FDA, EU CTR and ICH E2A provisions from those dates, including month ends and weekends.
Reclassification also matters. In the EU framework, a reaction first reported as non-fatal that later proves fatal or life-threatening starts a new 7-day period from when the sponsor learns of the change. Build a re-check into the process so follow-up information is reviewed on arrival, not at the next scheduled safety meeting.
A workable process
A short checklist for the safety section of your plan, whatever the region.
State the time limit, the form and who receives it, plus an out-of-hours contact. If the protocol lists events that are exempt from immediate reporting, name them.
Say who receives reports, who assesses causality and expectedness against the reference safety information, who decides on expedited reporting and who submits.
Site awareness, sponsor receipt, assessment and submission. Keep these separate from the event date.
List each country and each regulator with its recipient, format and period. Where there are several, track the earliest due date.
Define how follow-up information is reviewed and how a change in seriousness or causality restarts the process.
Run a mock event end to end, from the site form to the regulator submission, and time it.
In the data system
Safety reporting is mostly a data and timing problem. Capture includes safety reporting and adverse event forms in the same system as EDC, eConsent and ePRO, with one audit trail. That makes the dates auditable and puts the safety data next to the rest of the participant record.
Classification
Serious, unexpected, related
Site aware
Fri 12 Mar 2027, 09:00
Limits of this guide
This page orients you. It does not replace the regulations, your protocol or your regulatory affairs adviser. It does not classify events, and the line between serious, unexpected and related is a medical judgement against your reference safety information. It does not cover device vigilance, non-interventional studies, or the national regimes of countries outside the ones named. For US sponsors, the FDA IND guide for academics gives background on IND safety reports. For EU trials see EU CTR clinical trial software.
Rules also move. The UK changed in 2026, and EU and ICH texts are periodically revised. Check the current text before you finalise a safety plan.
The investigator reports a serious adverse event to the sponsor immediately or, in the EU, no later than 24 hours after becoming aware, unless the protocol sets something different. The sponsor then reports suspected unexpected serious adverse reactions to regulators on expedited clocks, commonly 7 days for fatal or life-threatening and 15 days for other qualifying reports.
Under 21 CFR 312.32, a sponsor reports unexpected fatal or life-threatening suspected adverse reactions as soon as possible and no later than 7 calendar days after initial receipt, and other qualifying IND safety reports no later than 15 calendar days after determining they qualify. Read the current regulation for the full list of reportable events.
Under Regulation (EU) 536/2014, a fatal or life-threatening SUSAR is reported as soon as possible and no later than 7 days after the sponsor becomes aware, and other SUSARs no later than 15 days. A reaction later found to be fatal or life-threatening starts a new 7-day period. Reports go through the EU system.
A summary of the UK Clinical Trials Toolkit lists fatal and life-threatening SUSARs within 7 days of first awareness. From 28 April 2026 the HRA says SUSARs go only to the MHRA. The period for other SUSARs is in MHRA guidance, so check the current text.
The FDA, EU and ICH deadlines are in calendar days, so a deadline falling on a weekend or holiday does not move. Some sponsors add an internal buffer. Check your own quality system and the regulator's text.
An SAE is any serious adverse event, regardless of cause. A SUSAR is a suspected unexpected serious adverse reaction: serious, reasonably possibly related to the investigational product, and not listed in the reference safety information. Only SUSARs and certain other findings trigger expedited regulatory reports.
No. Capture provides adverse event and SAE forms, a field-level audit trail, edit checks and exports in one system, so the data and dates are in one place. Submission to regulators is done through your own safety process and the regulator's systems.
The SAE reporting deadline calculator on this site takes the awareness, receipt and determination dates and returns due dates under the investigator 24-hour rule, FDA 21 CFR 312.32, the EU Clinical Trials Regulation and ICH E2A. It does not cover the UK.
Keep exploring
SAE reporting deadline calculator
Compute the due dates.
Serious adverse event decision tree
Is it serious, is it a SUSAR?
SUSAR reporting software
Sponsor-side workflow.
Adverse event reporting software
Capture events at the site.
SAE report form template
A form to start from.
Adverse event eCRF
The AE form in the library.
CTCAE grade lookup
Severity grading reference.
EU CTR clinical trial software
EU regulation overview.
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