Development and application of monoclonal antibodies to human cardiac myoglobin in a rapid fluorescence immunoassay

Myoglobin (Mb) is considered a useful marker for early detection of myocardial infarction and for monitoring cardiac reperfusion after thrombolytic therapy. We developed eight monoclonal antibodies to human cardiac Mb, characterized their epitopic reactivity, and determined which combinations of the antibodies are useful in two-site immunoassays. We configured two of the monoclonal antibodies in a one-step, two-site particle concentration fluorescence immunoassay (PCFIA) for measurement of Mb. The PCFIA has rapid kinetics of reaction, being complete in 15 min, and has a linear analytical range of 20-675 μg/L for human Mb. Although the PCFIA has a high dose ''hook'' effect, this is of no analytical importance at concentrations of Mb ≤148,000 μg/L. The assay is not subject to interference from icterus (bilirubin ≤360 mg/L), has no cross-reaction with hemoglobin (≤42 g/L), and may be performed with either plasma or serum in ~1 h. The intra- and interassay imprecisions (CV) of the method are <10% for concentrations of Mb within the normal range and <4% at higher concentrations. A comparison of the PCFIA with a commercial radioimmunoassay showed that results of the two assays correlate well (PCFIA = 0.88 x RIA + 18, r = 0.990, n = 171).