in accordance with the invention the term 34 analyte 34 refers to any substance or class of related substances whose presence is to be qualitatively or quantitatively determined in a sample fluid the present assay can be applied to the detection of analytes for which there is a specific binding partner and conversely to the detection of the capacity of an analyte medium to bind an analyte usually due to the presence of a binding partner for the analyte in the sample the analyte usually is an oligo or polynucleotide peptide protein carbohydrate glycoprotein steroid or other organic molecule for which a specific binding partner exists or can be provided by immunological or synthetic means the analyte in functional terms is usually selected from an rna or dna for which a complementary nucleic acid sequence exists or can be prepared antigens and antibodies thereto haptens and antibodies thereto and hormones vitamins metabolites and pharmacological agents and their receptors and binding substances the term 34 analyte specific moiety 34 refers to any compound or composite capable of recognizing a particular spatial and polar organization of a molecule i e epitopic site or a particular informational sequence such as a nucleic acid sequence in preference to other substances in the majority of embodiments the analyte specific moiety will be a specific binding assay reagent such as a nucleic acid hybridization assay probe or a polyclonal or monoclonal antibody or other specific binding protein in another aspect the analyte specific moiety can be a lectin which binds preferentially to a specific saccharide examples of particular interest include dna hybridization assay oligonucleotide probes such as those specific for disease causing organisms e g n.