Lactate dehydrogenase isoenzyme 1. A rapid assay for ischemic myocardial disease

A rapid immunochemical method (Isomune-LD) for the determination of lactate dehydrogenase isoenzyme 1 (LD1) activity in serum was investigated, and the sensitivity and specificity of the assay were determined for the diagnosis of a myocardial infarction (MI). Multiple serum samples were obtained (on admission and at 12, 24, and 48 hours) from 85 patients (30 with proven MI and 55 without MI). The sensitivity of LD1 on admission and at 12, 24, and 48 hours was 43%, 84%, 96%, and 100%, respectively, and the specificity at these same time intervals was 95%, 100%, 97%, and 97%, respectively. Thus, the determination of LD1 by this rapid immunochemical method appears to allow a rapid laboratory evaluation of MI with a high degree of sensitivity and specificity.