Electroosmophoretic radioimmunoassay: application to hepatitis-associated antigen.

Blumberg's discovery of the Australia antigen or hepatitis-associated antigen (HAA) and the subse quent demonstration of its relationship to serum hepatitis was a major contribution in the search for a method to eliminate carriers of serum hepatitis as potential blood donors (1,2). In a recent study of patients who had received blood transfusions that were serologically positive for HAA, three-fourths developed serum hepatitis, serum HAA, or an anti body response. Of those patients who had received blood that was serologically negative for HAA, 6% developed hepatitis (3). Possible explanations are that the techniques used for detecting HAA lacked either sensitivity or specificity for variants of the hepatitis etiological agent. It has been estimated that current, practical methodologies employed for the detection of HAA identify less than 50% of the carriers (4). Immunoelectroosmophoresis (IEOP) has achieved the most widespread use for screening prospective blood donors for HAA (5). Although IEOP lacks sensitivity for the detection of all sera containing HAA, it does lend itself to mass screening because of its speed (1 hr or less) and economy. Other in vestigators have applied radioimmunoassay (RIA) techniques to the detection of HAA and anti-HAA (6-9). Their methods are very sensitive, approxi mately 2—4orders of magnitude greater than that of the IEOP procedure. The major disadvantages of RIA techniques for mass screening have been time of analysis (1-6 days) and the cost of the required technological expertise. We have developed two rapid, sensitive radionuclide procedures for the de tection of hepatitis associated antigen and antibody that combine the speed and simplicity of IEOP with the sensitivity of RIA.