Which of the following is not a component of the scene size-up?

• A. Body substance isolation
• B. Mechanism of injury
• C. Initial assessment
• D. The location of all patients

Answer: (C)

Scene size-up is the quick evaluation of the environment and scene before touching the patient, focusing on safety and planning. It includes checking scene safety and protecting yourself with appropriate measures, considering the mechanism of injury or illness to anticipate injuries, determining how many patients are involved, and locating and coordinating needed resources. The location of all patients helps you organize access and movement, which is part of preparing for treatment on arrival.

The initial assessment, on the other hand, is a patient-specific, rapid check of vital functions—airway, breathing, circulation, and disability—to identify immediate life threats and establish priorities for care. This is done after you’ve completed the scene size-up and safety checks, not as part of the scene-size-up process itself. Therefore, the step not included in the scene size-up is the initial assessment.