Abstract: Methods are disclosed for determining an analyte in a medium suspected of containing the analyte. One method comprises providing (1) a medium suspected of containing the analyte, (2) a label reagent comprising a first specific binding pair (sbp) member associated with a photochemically activatable chemiluminescent compound wherein the first sbp member is capable of binding to the analyte or to a second sbp member to form a complex related to the presence of the analyte. The method further comprises photochemically activating the chemiluminescent compound. The amount of luminescence generated by the chemiluminescent compound is detected. The amount thereof is related to the amount of analyte in the medium. Compositions and kits are also disclosed.

Abstract: A method is provided for determining the presence in a sample of a member of a specific binding pair ("sbp member") consisting of ligand and its homologous receptor. The sample is combined in an aqueous medium with (1) a complementary sbp member wherein at least the sbp member or the complementary sbp member is bound to the surface of a cell and (2) a fuorescent agent capable of being incorporated into the cell. The presence of the sbp member is indicated by a change in fluorescence of the unseparated cell suspension as a result of agglutination of the cells.The present invention has particular application to blood typing, for example, for the determination of the presence of blood group antigens A, B, AB, O, and D (Rh.sub.o) and antibodies to such antigens.