A site reports a serious adverse event late. What checks and escalations are needed?

Short answer

Process the case at once so the sponsor's own regulatory clock is protected, then find out why it was late. Investigators must report SAEs to the sponsor immediately, which the EU Clinical Trials Regulation sets at no later than 24 hours. Check whether other events at the site were also late and whether any expedited report is now at risk.

Why

The sponsor's clock for expedited reporting starts when it becomes aware of the event, so a late site report shrinks the time left to assess it, not the deadline. If the event is a suspected unexpected serious adverse reaction (SUSAR), the EU requires reporting within 7 days if fatal or life threatening and 15 days otherwise. US IND safety reports have the same 7 and 15 calendar day limits under 21 CFR 312.32.

So the first action is to get the case to the safety team and medically assessed. Next, confirm the facts: when did the site know of the event, and why the delay? A participant admitted to another hospital may genuinely not have told the site for days, which is not a site failure.

A coordinator who held reports until the investigator signed is a process failure. Then check other participants' records for unreported or late SAEs, record the deviation, retrain, and escalate if the pattern suggests weak safety oversight. Endpoint events the protocol exempts from immediate reporting are a legitimate exception.

A strong answer covers

Protect the sponsor's expedited timelines first
Investigator reporting: immediately, and within 24 hours in the EU
SUSAR timelines of 7 and 15 days in EU and US
Distinguish when the site knew from when it reported
Look for a pattern across the site's other participants

Common mistakes

Believing the sponsor's regulatory clock starts when the site should have reported.
Investigating the cause before getting the case into safety processing.
Assuming every late report is site negligence when the site may have learned late.

The interviewer might ask next

How would you handle a protocol that exempts disease progression events from immediate SAE reporting?