[Usefulness of cardiac troponin I in patients with acute myocardial infarction].
Cardiac troponin(cTn) is a sensitive marker for acute myocardial infarction(AMI). However, some cases of renal failure have been reported to show false positive results for cardiac troponin T(cTnT). Recently, it has been reported that heart-type fatty acid-binding protein(H-FABP) is a sensitive marker for AMI in the early phase. We evaluated the usefulness of cardiac troponin I(cTNI) using serum samples from patients(age 57-96) confirmed to have AMI with chest pain(n = 48), unstable angina pectoris(n = 11), cardiac failure(n = 5), others with high creatine phosphokinase(CK) activity(n = 81) and renal failure(n = 28), by comparing among cTnT(qualitative and quantitative), H-FABP, CK and creatine phosphokinase isoenzyme MB(CK-MB) activity. The diagnostic validity of cTn was assessed by receiver operating characteristic(ROC) curve analysis. The cut off value for AMI of cTnI was 0.8 ng/ml, cTnT was 0.16 ng/ml and H-FABP was 19.0 ng/ml. The overall diagnostic sensitivity of cTnI was 83.1%, and 84.8% for cTnT (quantitative), 72.3% for cTnT(qualitative), 64.8% for H-FABP, 81.8% for CK and 59.3% for CK-MB. The overall diagnostic specificity of cTnI was 90.9%, and 81.3% for cTnT(quantitative), 60.5% for cTnT (qualitative), 53.2% for H-FABP, 52.9% for CK and 87.7% for CK-MB. The overall diagnostic efficiency of cTnI was 86.5%, and 82.7% for cTnT(quantitative), 63.6% for cTnT(qualitative), 59.8% for H-FABP, 69.0% for CK and 71.9% for CK-MB. False positive results for cTnI were found in a few cases with renal failure. cTnT(qualitative) showed false positive results in 22/28 with serum creatinine over 2.1 mg/dl due to renal failure. In conclusion, cTnI detection is considered a useful and sufficiently sensitive marker for AMI.
Ikeda
Jun
J
Department of Clinical Laboratory, Tokyo Metropolitan Geriatric Medical Center, Itabashi-ku, Tokyo, 173-0015.
Zenimoto
Mikio
M
Kita
Masami
M
Mori
Mayumi
M
D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D002352:Carrier Proteins / Q000097:blood; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D006801:Humans; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis*; D009363:Neoplasm Proteins; D012372:ROC Curve; D019210:Troponin I / Q000097:blood*; D025521:Tumor Suppressor Proteins
D015415:Biomarkers; D002352:Carrier Proteins; C107608:FABP7 protein, human; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D009363:Neoplasm Proteins; D019210:Troponin I; D025521:Tumor Suppressor Proteins