What does MCI stand for?

• A. Mass Casualty Incident
• B. Mass Critical Incident
• C. Medical Care Interaction
• D. Multi-Casualty Institute

Answer: (A)

In EMS, MCI stands for Mass Casualty Incident. This describes an event that overwhelms local resources because there are more patients than can be treated with routine capabilities. It requires rapid triage to sort patients by severity, incident command to coordinate responders, and often mutual-aid support and the use of staging areas and additional resources.

Think of situations like a major multi-vehicle crash or a large-scale disaster where several people are injured at once. The emphasis is on how to manage care across many patients efficiently, not on a single critical patient.

The other terms don’t fit the standard EMS usage. They aren’t recognized phrases for describing events with widespread injuries, and you won’t see them used in triage protocols or incident command systems.