Patent ID: 8288111
Filing Date: 2012-10-16
Classification: G01N

Abstract:
1. An immunoassay for assessing the amount of an analyte of interest in a test sample, wherein the analyte is a hydrophobic drug that metabolizes to form one or more cross-reacting metabolites, the immunoassay comprising the steps of: (a) contacting the test sample with one or more pretreatment reagents to form a first mixture, wherein the one or more pretreatment reagents lyse any cells and solubilize any analyte and cross-reacting metabolites present in the test sample; (b) contacting the first mixture with an antibody specific for the analyte to form a second mixture comprising a complex of the antibody with either analyte or metabolite, wherein the amount of antibody with which the first mixture is contacted is from about 0.1% to about 10% of the amount of analyte in the test sample; (c) washing the second mixture to remove any analyte and any metabolite not complexed with the antibody and to form a third mixture in which the analyte concentration is decreased to near the equilibrium dissociation constant (K (d) contacting the third mixture with a specific binding partner of the antibody labeled with a detectable label (“tracer”) to form a fourth mixture comprising a complex of the antibody with tracer (“antibody-tracer complex”); (e) washing the fourth mixture to remove any tracer not complexed with antibody; and (f) detecting the antibody-tracer complex as measure of the amount of analyte present in the test sample, wherein the immunoassay has less than about 10% cross-reactivity with any one or more cross-reacting metabolites present in the sample.