Patent ID: 8357495

Claim:
An immunoassay method for an analyte of interest in a biological sample that may contain endogenous anti-analyte antibodies, said method comprising: (a) contacting a biological sample being tested for analyte with a capture agent affixed to a solid phase, wherein the capture agent binds analyte, under conditions sufficient for binding of the capture agent to analyte to form a solid phase-affixed capture agent/analyte complex, and: (i) a detection agent that binds the analyte, under conditions sufficient for binding of the detection agent to any analyte present in the capture agent/analyte complex so as to form a solid phase-affixed detection agent/analyte/capture agent complex; and (ii) a species-specific antibody, wherein the species-specific antibody is specific for the species from which the biological sample was obtained and specifically binds endogenous anti-analyte antibody, under conditions sufficient for specific binding of the species-specific antibody to any endogenous anti-analyte antibody present in the sample and bound to the capture agent/analyte complex so as to form a solid phase-affixed species-specific antibody/endogenous anti-analyte antibody/analyte/capture agent complex; and (b) detecting analyte by detecting a signal from the solid phase-affixed complex(es) set forth in (a), wherein the signal is positively correlated with the concentration of analyte present in the sample.