The techniques described include the preparation of red cell or saliva specific ABH antibodies, the quantitation of red cell or saliva specific antigen, and the localization of Hr and Hs antigen in the salivary glands. Other procedures described pertain to the heterogeneity of Ulex europaeus anti-H (UE), the agglutinin activity of polymerized antibody, and the heat and chemical stability of group- specific antibodies in the state of immune complex. In describing blood grouping by ELISHA, the author reports that blood grouping with ELISHA yielded sensitivity 500 times higher than that obtained with the elution test. The extraction of ABH antigens from blood stains with ELISHA was done with various reagents; the most effective reagent was deoxy-BIGCHAP. ELISHA was also used to detect AB antigen from blood or body fluid stains and to detect separately ABH blood group of mixed stains of blood or body fluids. 7 tables, 1 figure, and 31 references