Evaluation of Diagnostic Efficiency of Troponin T Measurement in Acute Myocardial Infarction and Ischemic Heart Disease / 대한임상병리학회지

ABSTRACT

BACKGROUND: Troponin T(TnT), a 37 kDa polypeptide subunit of contractile protein, is part of the troponin complect in striated muscle, where it binds to tropomyosin. TnT is not usually found in circulating blood, but increase in serum by cytoplasmic damage. Because the amino acid sequence is unique to cardiac muscle, one can immunologically differentiate skeletal muscle and cardiac protein isoforms. METHODS: We evaluated serum cardiac TnT (ELISA, Troponin-T, Boehringer Mannheim, Germany) versos CK-MB mass (IMX CK-MB, Abbott Laboratories, USA) in 46 cases (173 samples) of acute myocardial infarction, 28 cases (94 samples) of ansi na pectoris, 23 cases (62 samples) of other cardiac disease, and 32 cases of non-cardiac disease from September 1994-June 1996. RESULTS: TnT was detected in serum(cutoff value 0.20 ng/ml) within 6 hours after onset of chest pain, slightly earlier than CK-MB mass (cutoff value 5.0 ng/ml). Sensitivity of TnT (81%) is not statistically different from CK-MB mass (84%) within 24 hour of cutest pain but more sensitive after 24-72 hours of symptom, Specificity (79.5%) and positive predictive value (70.7%) of TnT were superior to that of CK-MB mass within 24 fours of cutest pain, and persistent to 6 days, which was longer than that of Cl4-MB mass. More patients show increment of TnT in unstable angina pectoris(40.0%) than stable angina pectoris(15.4%), No difference in detection rate of TnT between angina pectoris(28.6%) and other cardiac disease patients(34.8%). Only 3.1 % of non-cardiac disease patients show TnT increment. CONCLUSIONS: We concluded that TnT Is not detected In most of non-cardiac disease patients, and is an early and later marker with very wide diagnostic time win-dow. Also, TnT can be used as a valuable masker for ischemic myocardial damage in any underlying causes.