Analytical and clinical performance of two cardiac troponin I immunoassays.
Cardiac troponin I assays for Axsym (Abbott Diagnostics, Abbott Park, IL, USA) and Immuno 1 (Bayer Corporation, Tarrytown, NY, USA) analysers were evaluated. Heparin plasma or serum could be used for both assays. Samples were stable for 24 h at ambient temperature, 3 days at 4-8 degrees C and 3 months at -20 degrees C. After 10 months' storage at -80 degrees C, the recoveries were well above 100% by both assays. Total coefficients of variation for Axsym assay were 9.0%, 5.8% and 5.3% at concentrations of 2.6 microg/l, 9.83 microg/l and 34.3 microg/l respectively; for Immuno 1 these were 4.4 %, 1.6% and 1.8% at 2.3 microg/l, 6.27 microg/l and 44.35 microg/l respectively. It was > or =20% at concentration of < or =0.5 microg/l for Axysm assay and < or =0.15 microg/l for Immuno 1 assay. Recoveries were < or =90% at < or =0.22 microg/l on Axsym and at < or =1.47 microg/l on Immuno 1. Neither method showed significant interference with haemoglobin, bilirubin, triglycerides or rheumatoid factor. Correlation between the two methods was excellent (r = 0.997, Y (Axsym) = 4.2X (Immuno 1) +3.2). The highest concentrations detected in 50 healthy subjects were 0.3 microg/l and 0.1 microg/l by Axsym and Immuno 1 methods, respectively. Twelve out of 43 renal failure patients had troponin I 0.13-0.9 microg/l using Axsym method and 4 had levels of 0.07-0.13 microg/l using Immuno 1. In muscle trauma patients, troponin I was undetectable.
Zaman
Z
Z
Department of Laboratory Medicine, University Hospitals Leuven, Belgium. zahur.zaman@uz.kuleuven.ac.be
De Spiegeleer
S
S
Gerits
M
M
Blanckaert
N
N
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers; D005260:Female; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D007676:Kidney Failure, Chronic / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009132:Muscles / Q000293:injuries; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D019210:Troponin I / Q000032:analysis*
D015415:Biomarkers; D019210:Troponin I