Serum myoglobin in the diagnosis of acute myocardial infarction

Serum myoglobin (Mgl) level was studied by the method of passive hemagglutination inhibition in 128 patients of whom 65 with acute myocardial infarction, 27 with unstable angina and 36 with various diseases as well as in 197 apparently normal subjects. The immunologic determination of serum myoglobin by the passive hemagglutination inhibition reaction was proved useful in the diagnosis of acute myocardial infarction (AMI) since in 95.3% of the cases myoglobin was found present in the serum in concentrations of 100-4.800 ng/ml depending on the moment of blood collection and the severity of infarction. The passive hemagglutination inhibition reaction for the determination of serum Mgl is superior to the biochemical tests (transaminases) both by the proportion of positive results obtained (95.3% by the Mgl test as compared with 73.8% by the transaminase test) and by its precocity, Mgl appearing in the serum within the first 1-2 hrs after onset of infarction. In the cases of AMI with negative or uninterpretable biochemical tests and/or ECG, serum Mgl determination can be decisive for the diagnosis. The presence of serum Mgl in 37.5% of the cases with intermediary syndrome (unstable angina) suggests the existence of some microfoci of myocardial necrosis undetectable by the usual biochemical or electric methods. Serum Mgl determination by the passive hemagglutination inhibition reaction is a relatively simple method, rapid (the results are obtained 1-2 hrs after blood collection) and practical since it can be performed in any laboratory with the usual equipment.