The levels of serum myoglobin in cardiac patients with elevated creatine kinase‐MB and suspected acute myocardial infarction

A monoclonal antibody enzyme immunoinhibition assay was used to quantitate serial serum myoglobin (Mb) levels in 121 patients who had ≫5% creatine kinase‐MB (CK‐MB) and suspected acute myocardial infarction (AMI). Serum Mb levels higher than 0.16 μg/ml were considered abnormal. In 94% of these patients who were finally diagnosed with AMI, Mb levels were higher than 0.16 μg/ml, whereas all 30 normal control blood donors had lower Mb levels. Patients with anterior or inferior wall infarcts had higher Mb levels (≫0.64 μg/ml) than patients with lateral or subendocardial infarction. Only 68% (82/ 121) of patients evaluated by elevated CK‐MB alone had a final diagnosis of AMI. In contrast, 94% (77/83) of patients who in addition showed elevated Mb had AMI. It is suggested that analysis of Mb levels allows a more accurate diagnosis of AMI in patients with elevated CK‐MB than does reliance on CK‐MB values alone. © 1993 Wiley‐Liss, Inc.