EVALUATION OF A NEW BIOLOGICAL ASSAY FOR EMERGENCY QUANTIFICATION OF SERUM MYOGLOBIN

The usefulness of a nephelometric-based serum myoglobin assay kit in the early diagnosis of acute myocardial infarction was assessed in 92 consecutive patients admitted within 24 hours of the onset of spontaneous chest pain lasting greater than or equal to 20 minutes. The discharge diagnosis was acute myocardial infarction in 37 patients (40.2%), myocardial infarction lasting greater than or equal to 6 hours in 10, and no myocardial infarction in 45 (48.9%). The characteristic curve showed that the best differential diagnostic value was a serum myoglobin greater than or equal to 130 mu g/l (sensitivity, 75.6%; specificity, 91.7%; positive-predictive value, 88%; negative-predictive value, 82%). The initial diagnosis was doubtful in 33 patients (36%) because of an inconclusive electrocardiogram. A serum myoglobin value of greater than or equal to 130 mu g/l would have identified 9 of the 13 patients with acute myocardial infarction and all of the 20 patients without myocardial infarction, giving an accuracy of 84.8%. These results suggest that this new rapid, quantitative serum myoglobin assay would be useful in the evaluation of suspected myocardial infarction, especially in patients with an inconclusive electrocardiogram.