Evaluation of a new troponin I method on the Bayer Immuno 1 immunoassay analyser.
We have evaluated the analytical and clinical performance of an automated immunoassay for serum cardiac troponin I (Bayer Immuno 1TM, Bayer Diagnostics, Tarrytown, NY). The between batch imprecision was found to be between 1.2 and 3.2% over the concentration range 2.5 - 34.0 microg/L. The analytical range obtained from duplicate analysis of patient samples and defined as a coefficient of variation of 10% or less was 0.3 - 200 microg/L. The detection limit was found to be less than 0.1 microg/L. A method comparison with the Dade Stratus method (Dade Behring, Wilmington, DE) yielded regression statistics with a slope of 0.705 and an intercept of -0.260. An analysis of samples from 40 patients with renal failure demonstrated six with detectable levels of troponin I (0.2 - 1.9 microg/L). Samples from patients with paraproteinaemia did not demonstrate detectable troponin I (from n = 30); however, two patients with elevated rheumatoid factor titers (from n = 20) demonstrated a detectable amount of troponin I (0.1 and 0.2 microg/L). In a study of 100 patients admitted with acute chest pain and a diagnosis of unstable angina, 6 were subsequently diagnosed as having suffered a myocardial infarction. On admission the sensitivity and specificity of the troponin I results were 26.7% and 94.7%, respectively, moving to 100% and 83% 12 hours after admission.
Clark
G H
GH
Department of Clinical Biochemistry, Barts and The London NHS Trust, Whitechapel, London, UK.
Kennon
S R
SR
Price
C P
CP
D000704:Analysis of Variance; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation*; D009203:Myocardial Infarction / Q000097:blood*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D019210:Troponin I / Q000097:blood*
D019210:Troponin I