Cardiac troponin-T immunoassay for diagnosis of acute myocardial infarction.
We evaluated the analytical and clinical performance of an immunoassay for cardiac troponin T (cTnT). Within-run and total imprecision ranged from 1.6 to 11.3%. The sensitivity and linear range was 0.015 and 13 micrograms/L, respectively. Frozen samples were stable for at least 8 weeks. No interferences were seen with lipids or bilirubin (total and conjugated). Hemoglobin caused a negative bias at concentrations > 4 g/L. Heparinized plasma showed a 6% negative bias compared with serum. The clinical utility of cTnT was compared with that of creatine kinase (CK)-MB (mass assay). The sensitivity of cTnT measurements from 63 patients with acute myocardial infarction (AMI) (cTnT cutoff 0.1 microgram/L) was 60% at 0-3 h, 59% at 3-6 h, 94% at 6-9 h, 90% at 9-12 h, 99% at 12-24 h, 92% at 24-48 h, 83% at 48-72 h, and 100% at 72-96 h. Corresponding results for CK-MB (cutoff 5.0 micrograms/L and 2.5% relative index) were 45%, 64%, 82%, 97%, 87%, 81%, 54%, and 59%. The specificity of the markers from 49 non-AMI patients was 46% and 79% for cTnT and CK-MB, respectively. We show that CK-MB is more specific for diagnosis of AMI, and propose that cTnT is more sensitive to myocardial injury.
Wu
A H
AH
Department of Pathology, Hartford Hospital, CT.
Valdes
R
R
Apple
F S
FS
Gornet
T
T
Stone
M A
MA
Mayfield-Stokes
S
S
Ingersoll-Stroubos
A M
AM
Wiler
B
B
D001663:Bilirubin / Q000097:blood; D003402:Creatine Kinase / Q000097:blood; D004355:Drug Stability; D005188:False Negative Reactions; D005615:Freezing; D006454:Hemoglobins / Q000032:analysis; D006493:Heparin / Q000097:blood; D006801:Humans; D007118:Immunoassay / Q000379:methods* / Q000706:statistics & numerical data; D007527:Isoenzymes; D008055:Lipids / Q000097:blood; D009203:Myocardial Infarction / Q000097:blood / Q000175:diagnosis*; D009206:Myocardium / Q000737:chemistry*; D012016:Reference Values; D012680:Sensitivity and Specificity; D013997:Time Factors; D014336:Troponin / Q000097:blood*; D020107:Troponin T
D006454:Hemoglobins; D007527:Isoenzymes; D008055:Lipids; D014336:Troponin; D020107:Troponin T; D006493:Heparin; D003402:Creatine Kinase; D001663:Bilirubin