Early diagnosis of acute myocardial infarction: CK-MB and myoglobin compared.

We have measured changes in plasma concentration of creatine kinase MB (CK-MB) and myoglobin in 50 patients admitted to the Coronary Care Unit with chest pain of presumed cardiac origin. Eight serial blood samples were obtained in the 6 h period following admission and both CK-MB and myoglobin concentrations were measured. We compared the performance of single values of both tests. Myoglobin concentration, in the coronary care population studied, proved to be as specific as CK-MB concentration (92.6% in both cases) but with sensitivity of 100% being achieved 1.5 h post admission rather than 4 h post admission in the case of CK-MB. On this evidence, measurement of plasma myoglobin could prove useful in the rapid diagnosis of myocardial infarction with consequent effects on optimal Coronary Care utilisation and selection of patients for thrombolytic therapy.