Hemagglutination assay for antigen and antibody associated with viral hepatitis

Hemagglutination assays are described for measuring hepatitis-associated Australia antigen and antibody. Red cells coated with isolated antigen, with chromic chloride as a coupling agent, are used for detection of antibodies. Detection of the antigen in serums depends on inhibition of hemagglutination. The test has the sensitivity and rapidity of the best tests available, is simpler to perform, and lends itself to large-scale screening of blood donors.