A 0/1-Hour Protocol to Assess for Non–ST-Segment Elevation Myocardial Infarction

A protocol has been proposed to assess patients for non–ST-segment elevation myocardial infarction (NSTEMI), based on high-sensitivity troponin T (hsTnT) or I (hsTnI) measurements at presentation and 1 hour later (in conjunction with clinical and electrocardiographic factors). The protocol uses specific assay cutoffs to allow early triage into three groups: A “rule-in” group (MI is likely), a “rule-out” group (MI is excluded with good confidence), and an “observe” group with intermediate results.

To validate the protocol's performance, investigators pooled data from two studies. In a study involving hsTnI, only 0.3% of 1533 patients triaged to the rule-out category ultimately had NSTEMI (negative predictive value, 99.7%), whereas 62% of 800 …