Equivalent early sensitivities of myoglobin, creatine kinase MB mass, creatine kinase isoform ratios, and cardiac troponins I and T for acute myocardial infarction.

Early sensitivities of creatine kinase (CK), CKMB (activity and mass), CKMM and CKMB isoform ratios, myoglobin, cardiac troponin I (cTnI), and cardiac troponin T (cTnT) were compared to find the most sensitive serum marker for acute myocardial infarction (AMI) during the first hours after onset of chest pain. In a prospective study we investigated 37 consecutive patients with AMI who were admitted to the coronary care unit within 4 h after onset of chest pain. Blood samples were drawn every hour for the first 10 h after admission. CKMB mass concentrations, CKMM and CKMB isoform ratios, myoglobin, cTnI, and cTnT increased significantly (P < or = 0.0067) earlier than CK and CKMB activity and were also significantly (P < or = 0.046) and markedly more sensitive on admission. Differences in early sensitivities of myoglobin, CKMB mass, CK isoform ratios, cTnI, and cTnT were small and not significant. Therefore, turnaround time and practicality for emergency determination of methods, specificities of markers, the required specificity in the individual patient, and costs mainly determine the choice among myoglobin, CKMB mass, CK isoforms, cTnI, and cTnT.