PLASMA MYOGLOBIN IN THE EARLY DIAGNOSIS OF ACUTE MYOCARDIAL-INFARCTION

Serum and plasma myoglobin and creatine kinase-MB catalytic activity w ere analysed in 157 patients admitted within 2 hours of the onset of c hest pain (58 were retrospectively recognized as acute myocardial infa rction). Serum and plasma values were highly correlated for both myogl obin and creatine kinase-MB. Plasma myoglobin appared to be more sensi tive than creatine kinase-MB for the early diagnosis of acute myocardi al infarction; using a cut-off value of 100 mug/l, 90% of acute myocar dial infarction cases were correctly recognized by plasma myoglobin 6 hours after the onset of chest pain, with a diagnostic specificity of 100% for non-acute myocardial infarction chest pain subjects. Plasma c reatine kinase-MB showed a diagnostic sensitivity of 62% and a diagnos tic specificity of 95% in the same group of patients. We suggest the i nclusion of the plasma myoglobin immunonephelometric assay together wi th plasma creatine kinase-MB activity analysis in protocols for the ea rly diagnosis of acute myocardial infarction.