Measurement of human ventricular myosin light chain‐1 by monoclonal solid‐phase enzyme immunoassay in patients with acute myocardial infarction

A monoclonal solid-phase enzyme immunoassay has been developed for the detection of human serum ventricular myosin light chain-1. Cross-reactivity of this with human skeletal muscle myosin was observed, but the enzyme immunoassay with the sera of patients with acute myocardial infarction gave similar results with radioimmunoassay. The human ventricular myosin light chain-1 levels in the healthy subjects were 0.2-6.6 ng/ml in males and 0.2-4.1 ng/ml in females. Within-run and between-run precision (CVs) of the assays was on the order of 2.3-4.7% and 4.3-8.7, respectively. Sensitivity of the assay was 1.0 ng/ml, and working range was 5-100 ng/ml. In all patients with define acute myocardial infarction, serum ventricular myosin light chain-1 levels increased three- to ten-fold the upper reference range within 6 hr after the onset of chest pains. Two types of subtrend were discovered: its levels remain elevated for 3-4 days and its levels increased and then decreased 1-2 days after the initial rise but became elevated again for the next 4-7 days after the onset of chest pain, which is in contrast to the case with all conventionally used biochemical cardiac markers.