Abstract: A compound for use as a chemiluminescent label in immunoassay comprises an aryl acridinium ester linked to an N-succinimidyl moiety. The compound is conveniently linked to a monoclonal antibody or other protein and is used in a two-site immunoassay for the quantitation of an antigen of interest, by initiation of the luminescent reaction and subsequent measurement of the photonic emission of the immune complex formed during the immunological reaction.

Abstract: The invention relates to a method of detecting, analyzing, quantifying or locating a protein, antibody, antigen, hapten, hormone, metabolite, nucleic acid or steroid, in which the substance of interest is linked to a chemi-luminescent or bio-luminescent label. A luminescent reaction is then triggered by the addition of an oxidizing agent or a catalyst and the emitted light is observed in order to provide information about the substance. The invention employs a luminescent reagent which consists of antibodies labelled with a luminescent material such as luminol. The luminescent reagent can be used to quantify antigens in an immunological assay. The luminescent labelled antibodies selectively bind to the antigens and the amount of light emitted in a luminescent reaction gives an indication of the amount of antigens present. A luminescent labelled substance can also be reacted with an antibody or antigen labelled with a fluorescent material in order to carry out a homogeneous assay.