Selection of plasma for hepatitis B immune globulin using a low cost radioimmunoassay.

Polystyrene beads coated with pasteurised polyethylene glycol-precipitated HBsAg were used to detect anti-HBs by a solid phase inhibition assay employing unreacted 125I-anti-HBs which had previously been "processed" by polyethylene glycol precipitation and used to test for the HBsAg. A weak anti-HBs (approximately 0.1 IU/ml) positive control was used to establish a target level of reactivity. 16,035 freshly donated units of blood, a 90-sample coded anti-HBs panel and a selection of hyperimmune globulins were investigated. All positive results were confirmed by a standard commercial assay. Antibody content of selected samples was quantitated in international units. A target level of anti-HBs activity is suggested for donor plasma to be fractionated for the production of hepatitis B immune globulin.