Patent ID: 7863057

Claim:
A method for detecting an analyte in a test solution comprising: a) configuring a binder for generating a detectable signal, the binder capable of combining with an analyte from the solution to form a binder-analyte complex; b) immobilizing, within a test zone of a test strip, a test zone capture agent; c) immobilizing, within a single control zone of a strip, a plurality of control zone capture agents, each of the plurality of control zone capture agents having different affinity to the binder and each able to capture the binder; d) applying the binder to the test strip; e) applying the test solution to the test strip, wherein the test solution and the binder combines to allow binding of analyte to binder to form a binder-analyte complex; f) capturing binder unbound by analyte in the test zone; g) capturing the binder, whether or not the binder has formed a binder-analyte complex, at the control zone; h) comparing the signal in the control zone to the signal in the test zone to determine the presence of analyte in the solution, wherein a greater signal in the control zone, as compared to the test zone, indicates a positive result.