Which emergency medical dispatch codes predict high prehospital nontransport rates in an urban community?

Background: The Medical Priority Dispatch System (MPDS) is a commonly used computer-based emergency medical dispatch (EMD) system that is widely used to prioritize 9-1-1 calls and optimize resource allocation. There are five major priority classes used to dispatch 9-1-1 calls in the San Francisco System; Alpha codes are the lowest priority (lowest expected acuity) and Echo are the highest priority.

Objective: We sought to determine which MPDS dispatch codes are associated with high prehospital nontransport rates (NTRs).