Application of a galactosidase immunosorbent test to carcinoembryonic antigen in plasma

The galactosidase immunosorbent test for carcinoembryonic antigen is simple to perform, uses stable reagents, does not require radioactive reagents, and is adaptable to large numbers of samples. Concentration of carcinoembryonic antigen in sera or plasma was determined by the galactosidase immunosorbent test and by the Egan-Todd double antibody assay (93% agreement), indirect Z-gel (83% agreement), and direct Z-gel assay (ps = 0.97). The galactosidase immunosorbent test has potential as a clinically useful nonisotopic assay for carcinoembryonic antigen.