Evaluation of a point-of-care system for quantitative determination of troponin T and myoglobin

We present the results of a multicenter evaluation of a new point-of-care s ystem (Cardiac Reader) for the quantitative determination of cardiac tropon in T (CARDIAC T Quantitative test) and myoglobin (CARDIAC M test) in whole blood samples. The Cardiac Reader is a CCD camera that optically reads the immunochemical test strips. The measuring range is 0.1 to 3 mu g/l for CARDIAC T Quantitat ive and 30 to 700 mu g/l for CARDIAC M. Both tests are calibrated by the ma nufacturer. The reaction times of the tests are 12 or 8 minutes, respective ly. Method comparisons were performed with 281 heparinized blood samples from p atients with suspected acute coronary syndromes. The results obtained with CARDIAC T Quantitative showed a good agreement compared with cardiac tropon in T ELISA (r = 0.89; y = 0.93x + 0.02). The method comparison between CARD IAC M and Tina-quant Myoglobin also showed a good agreement between both as says (r = 0.98; y = 0.92x + 1.6). Test lot-to-lot comparisons yielded diffe rences of 2% and 6% for CARDIAC T Quantitative and of 0 to 11% for CARDIAC M. The within-run imprecision with blood samples and control materials was acc eptable for CARDIAC T Quantitative (CV 10 to 15%) and good for CARDIAC M (C V 5 to 10%). The between-instrument CV was below 7% for CARDIAC T Quantitat ive and below 5% for CARDIAC M. The cross-reactivity of CARDIAC T Quantitative with skeletal troponin T was approximately 0.003%. No significant analytical interference was detected for any of the assays in investigations with biotin (up to 100 mu g/l), hem oglobin (up to 0.125 mmol/l), hematocrit (26 to 52%), bilirubin (up to 340 mu mol/l), triglycerides (up to 5.0 mmol/l), and 18 standard drugs. With the Cardiac Reader reliable quantitative results can be easily obtaine d for both cardiac markers. The system is, therefore, particularly suitable for use in emergency rooms, coronary care units and small hospitals.