A latex particle assay for platelet-associated IgG

A modified, sensitive, solid-phase assay for platelet-associated IgG is reported. Direct comparisons were made between a 125I monoclonal radioimmunoassay (RIA) and the polyclonal antibody latex particle assay. In 209 simultaneous comparisons with the RIA, the sensitivity of the latex test was 91 percent, specificity was 100 percent, and overall efficiency was 97 percent. Commencing with platelet-rich plasma, the direct latex particle test for platelet-bound IgG requires 45 minutes; 90 minutes are required to crossmatch one patient with 12 donors. The advantages of the latex assay are absence of radioactivity, stability of reagents, economy, speed, specificity, and sensitivity.