Purpose: To identify calls “under-triaged” by priority medical dispatch and determine causes and pre-hospital outcomes.

Methods: 6 month retrospective analysis identified calls dispatched “low priority” to which medics assigned “high acuity” transports (acute status or requiring ALS meds; not just IV/O2/monitor). CAD data, paramedic run-sheets, and audiotapes were reviewed to determine optimal dispatch levels and transport codes. “Under-triage” was defined as calls warranting “high priority” dispatch based on evidence from the run-sheet. Dispatcher, calling party, and patient data influencing “undertriage” were assessed.

Results: In 1995, 11,178/70,887 (16%) medical aid requests were dispatched “low priority”. 201(1.8%) were subsequently assigned “high acuity” transport codes by paramedics. 105/5,737 such consecutive patients were analyzed from July-December 1995. 6 were excluded due to incomplete data. After review, 42/99 actually warranted “high priority” dispatch. 7 had potential life/limb threatening injuries; 35 required ALS intervention. None had adverse prehospital outcome. Undertriage was associated with dispatcher error, information relayed from law enforcement officers (OR =3.4, CI: 1.2-10) calls involving alcohol (OR = 2.8, CI: 0.9-9.2) or patients with ALOC(OR= 3.4, CI: 1.2-10).