Detection and quantitation of platelet-associated IgG in thrombocytopenia: a comparison of immunofluorescence and immunoenzyme techniques.

A platelet suspension immunofluorescence test (PIFT) was compared with an enzyme-linked immunosorbent assay (ELISA) for measurement of platelet-associated IgG (PAIgG) in 108 patients with thrombocytopenia. The ELISA appeared to have greater sensitivity than the PIFT in detecting PAIgG in patients with idiopathic thrombocytopenic purpura, and in other groups of patients studied, and in many cases results were discrepant between the two assays. Possible explanations are given for the low sensitivity of the PIFT, and for the discrepant results.