Prehospital testing for troponin T in patients with suspected acute myocardial infarction

Background Cardiac troponin T (TnT) is a highly sensitive and specific mark er for myocardial damage and can be detected early after myocardial injury. Our hypothesis was to use TnT as an objective marker to verify acute myoca rdial infarction before hospital admission. Methods and Results We evaluated the sensitivity of a rapid qualitative ass ay for serum TnT for the detection of acute myocardial infarction in the am bulance and assessed the predictive value of a positive prehospital TnT tes t for death and myocardial infarction during 6-months of follow-up. The stu dy, conducted in an urban area, included 158 consecutive patients with susp ected acute myocardial infarction (93 men aged 69 +/- 13 years). A myocardi al infarction was confirmed in 40 and excluded in 118 patients. The prehosp ital TnT test was positive in 11 patients, of whom 7 had acute myocardial i nfarction. Fifty-three patients had a positive test result at hospital admi ssion, with evidence of myocardial infarction in 39 of them. The sensitivit y to acute myocardial infarction was 18% for the prehospital and 98% for th e in-hospital test with 78% and 88% specificity, respectively. During follo w-up, patients with a positive prehospital TnT test result had cardiac even ts more often (9 of 11) than patients with a negative result (26 of 147; P <.0001). Conclusions In areas with short transport times to the patient the rapid Tn T test performed at the point of care identified only a minority of the pat ients with acute myocardial infarction. A positive prehospital TnT test res ult seems to be an objective marker For a worse outcome in patients present ing with suspected acute myocardial infarction.