What is a sentinel event?

• A. An unexpected occurrence involving death or serious psychological injury that requires immediate investigation.
• B. A planned safety drill
• C. A minor medication error without harm
• D. An unexpected occurrence requiring immediate investigation and reporting

Answer: (D)

Sentinel events are unexpected patient safety events that signal a serious issue in care and require urgent investigation and formal reporting to the appropriate authority. The essential point is that these events go beyond routine incidents—they have significant harm or the risk of significant harm, and they prompt a formal root-cause analysis to prevent recurrence. That combination—being unexpected and needing both immediate investigation and reporting—is what sets a sentinel event apart. The other scenarios either describe planned activities, minor errors, or only call for investigation without the reporting requirement, or they narrow the harm to a type (like psychological injury) that isn’t the defining trigger in standard definitions.