Role of troponin T and I in acute myocardial infarction

ABSTRACT

The study was consisted of one hundred patients admitted to the CCU with chest pain diagnosed as AMI and non-AMI diagnosed according to the WHO criteria. Fifty patients [30 males and 20 females, age 42 to 65 years] with AMI and 50 patients [36 males and 14 females, age 45 to 65 years] with non-AMI. Serum aliquots were taken from routine cardiac enzyme [total CK, CK-MB activity] and samples were collected from patients in the CCU. The blood samples were collected in evacuated gel tubes for serum preparation and allowed clotting at room temperature before centrifugation. Serum aliquots were stored at '70°C for later batch analysis of other cardiac markers [TnT, TnI] then thawed once just before analysis. Troponin-I was measured on AxSYM, Aboote Laboratories, Abbott Park, IL, USA. Troponin-T was measured on Elecsys 1010, Boehringer Mannheim, Mannheim, Germany. The median and range values of the cardiac markers was 3.3 [0.01-25] ng/ml in AMI and 0.1 [0.01-1-4] ng/ml in non-AMI patients for Troponin-T. The corresponding values for Troponin-I in AMI patients was 50 [0.4-50] ng/ml and 1.0 [0- 5] ng/ml in non-AMI patients. The sensitivity and specificity at the specified cutoffs for all patients are shown in Table I. There were 17 false negative results for troponin-T and 23 false negative for troponin-I at admission. However, at 12-24 hours after admission, there was only one false negative for troponin-T and three false negatives for troponin-I. There was also one false positive for troponin-I in patients with pulmonary edema, and two false positive for troponin-T in patients with end-stage renal failure and cardiomyopathy. The two false positive troponin-T results that were coming from 2 patients, diagnosed as cardiomyopathy, complicated with renal failure