Cardiac troponin I for the diagnosis of acute myocardial infarction in the emergency department.

Cardiac troponin I (TnI) was tested in 316 consecutive patients with chest pain who were admitted to the emergency department, of whom 62 were discharged with a diagnosis of acute myocardial infarction (AMI). The TnI level was abnormal in 49 patients with AMI compared with 27 for creatine kinase (CK)-MB in the first specimen obtained at admission. All 62 patients with AMI were correctly diagnosed at admission with a combination of TnI and myoglobin testing. The overall peak performance of TnI testing in samples received within 24 hours of admission indicated high sensitivity (97%) and specificity (98%) for the diagnosis of AMI. The TnI was positive in elderly patients with myocardial injury and low CK and normal CK-MB values. These data suggest that testing for TnI could replace CK-MB and, in combination with myoglobin, could facilitate the rapid and effective triage of patients with chest pain in the emergency department.