Abstract: A sensitive direct immunoassay system is provided for the detection of an antigen in body fluids. A single antibody which reacts with an antigen or antigens and which is bonded to an insoluble member, is incubated with a test sample. During this first period of incubation a portion of an antigen present in the test sample will combine with the antibody immobilized on the insoluble member. The antibody bonded member, to which antigen is attached, is then washed and incubated with an enzyme tagged antibody reagent. During the second incubation, the tagged antibody reacts with antigen fixed to the antibody member in the first incubation. Thus, an immobilized "sandwich" is formed of an insoluble member- antibody-antigen-enzyme tagged antibody. After the second incubation, the member is washed again to remove unreacted enzyme antibody reagent. The member is then exposed to a substrate which is converted by the enzyme to produce an end product.

Abstract: A sensitive direct immunoassay system is provided for the detection of an antigen associated with hepatitis in body fluids. A single antibody which reacts with a hepatitis antigen or antigens and which is bonded to an insoluble member, is incubated with a test sample. During this first period of incubation a portion of an antigen present in the test sample will combine with the antibody immobilized on the insoluble member. The antibody bonded member, to which antigen is attached, is then washed and incubated with an enzyme tagged antibody reagent. During the second incubation, the tagged antibody reacts with antigen fixed to the antibody member in the first incubation. Thus, an immobilized "sandwich" is formed of an insoluble member- antibody-antigen-enzyme tagged antibody. After the second incubation, the member is washed again to remove unreacted enzyme antibody reagent. The member is then exposed to a substrated which is converted by the enzyme to produce an end product.

Abstract: A disc-shaped insoluble matrix is formed of a polymeric material having a layer of reactive groups which react with proteins binding them covalently and uniformly to its surface. An antibody adapted for use in immunoassay of antigens associated with hepatitis is covalently bonded to the reactive groups. The matrix is provided with irregular, e.g., waffle-like, surfaces designed to increase the amount of antibody that will be in contact with a test solution such as serum.

Abstract: A test set useful for detecting the presence of antigens associated with hepatitis comprising an insoluble, polymeric disc-like solid having antibody reactive with antigens associated with hepatitis bonded thereto, an enzyme-hepatitis antibody conjugate reagent, an enzyme substrate solution, control sera negative, weakly positive, and strongly positive for antigens associated with hepatitis, an enzyme substrate buffer, and a horse globulin solution. Preferably, the enzyme of the conjugate is alkaline phosphatase, the enzyme substrate is p-nitrophenylphosphate and the substrate buffer has a pH on the order of 9.8.