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: Assay methods are provided for determining an analyte in a sample suspected of containing the analyte. The method is carried out using a composition that includes a conjugate of a first sbp member with a particle. A luminescer is reversibly associated with a nonaqueous phase of the particle. Where the first sbp member is not complementary to the analyte, a second sbp member that is capable of binding to the first sbp member is employed. Unbound conjugate is separated from conjugate that is bound to the analyte or to the second sbp member. A reagent for enhancing the detectability of the luminescer is added and the light emission of the luminescer acted on by the reagent is measured.