Diagnostic Efficiency of a Point-of-Care System for Quantitative Determination of Troponin T and Myoglobin in the Coronary Care Unit

This study was carried out to compare the time-dependent diagnostic sensitivity and specificity for acute myocardial infarction of 2 point-of-care tests for troponin T and myoglobin measured in routine use of coronary care units with those of the respective laboratory tests. A total of 794 consecutive patients with suspected acute coronary syndromes admitted to the coronary care units of 6 hospitals were enrolled in the study. Point-of-care tests and laboratory tests were measured in parallel from samples obtained serially on admission, and at 1, 2, 4, 6 to 8, 12, 24, and 48 hours from admission. The point-of-care tests achieved maximum sensitivities of 96% (troponin T) and 72% (myoglobin); and the maximum sensitivities of the laboratory tests were 96%, 81%, and 83% for troponin T, myoglobin, and CK-MB mass respectively. The specificities varied from 90 to 94% for point-of-care troponin T, 83 to 93% for point-of-care myoglobin, 97 to 99% for laboratory troponin T, 79 to 85% for laboratory myoglobin, and 95 to 100% for laboratory CK-MB mass. The following maximum areas under receiver-operator characteristics curves were obtained (at different times): point-of-care troponin T, 0.97; point-of-care myoglobin, 0.87; laboratory troponin T, 0.99; laboratory myoglobin, 0.89; and laboratory CK-MB mass, 0.96. In conclusion the point-of-care tests had a comparable clinical performance as established cardiac markers performed in the laboratory.