Quantitative bedside assay for cardiac troponin T: A complementary method to centralized laboratory testing

Background: In the evaluation of chest pain patients, whole blood bedside a ssays of highly specific cardiac molecules may be an attractive alternative to centralized clinical chemistry testing. We now report on an optimized t est strip device for cardiac troponin T (cTnT) that can be analyzed by a ca rdiac reader for quantitative assessment of the test result. Methods and Results: The cTnT test strip reader measures, via a CCD camera, the reflectance of the signal line. For quantitative analysis, a calibrati on curve was constructed from 1030 samples of 252 consecutive patients with acute coronary syndromes. In a method comparison of 140 samples, the quant itative results of the cTnT test strip reader correlated closely with the r esults of the cTnT ELISA (r = 0.98; y = 0.85x + 0.002). Within-run and day- to-day (n = 10) mean CVs were between 11% and 16%, respectively. The cross- reactivity with skeletal troponin T tvas <0.02%. In patients with myocardia l infarction, 45% and 91% of all samples were positive on admission and at 4-8 h after the onset of symptoms, respectively. ROC curve analysis demonst rated a comparable efficiency of the cTnT test strip reader and the laborat ory-based cTnT ELISA in patients with suspected myocardial infarction. Conclusions: It is now possible to quantitatively determine cTnT at the pat ient's bedside with a rapid and convenient test device. This will facilitat e the diagnostic work up of patients with suspected myocardial cell necrosi s. (C) 1999 American Association for Clinical Chemistry.