Study of a myoglobin test in patients hospitalized for suspected myocardial infarction.

An immunoagglutination latex test was studied in comparison with a plasma myoglobin radioimmunoassay in 103 subjects with suspected myocardial infarction. The test provided an early and reliable indication of raised plasma myoglobin (greater than 85 micrograms/l), a biochemical marker for the early phase (12 h) of myocardial infarction. The diagnostic values (sensitivity and specificity) studied over a 36 h period were the same as those for the plasma myoglobin assay. The sensitivity was similar to that of creatine kinase activity and better than that of the creatine kinase MB/creatine kinase ratio; the lower specificity was due to false-positive results in some subjects with angina. The myoglobin test, which provides rapid results, may be substituted in early diagnosis of myocardial infarction for the plasma myoglobin assay which is unsuitable for emergency analysis.