Patent ID: 8354235

Claim:
A method for determining the concentration of an analyte in a sample comprising: a) providing a test element comprising at least one first zone and at least one second zone; b) contacting the sample with the test element and at least one detectable binding partner capable of specific binding reaction with the analyte; c) forming a complex comprising at least said detectable binding partner, said analyte, and an immobilized binding partner comprising an analyte specific antibody localized in said first zone; d) forming a complex comprising at least said detectable binding partner said analyte, and an immobilized binding partner comprising an analyte specific antibody localized in said second zone; e) measuring a first detectable signal (NS) in the first zone, wherein said first signal is dependent on the amount of said analyte in said sample; f) measuring a second detectable signal (KS) in the second zone, wherein said second signal is also dependent on the amount of analyte in the sample; g) offsetting said first and said second signals using one of the following algorithms: [KS(0)-KS(c)] + [(NS(0)-NS(c)], [KS(0)-NS(c)] * [NS(0)-NS(c)], and KS(c):NS(c), wherein, NS(0)=signal in the first zone at an analyte concentration 0; NS(c)=signal in the first zone at an analyte concentration c; KS(0)=signal in the second zone at an analyte concentration 0; and KS(c)=signal in the second zone at an analyte concentration c, h) comparing the offset of said first and said second signals with a calibration curve; and i) determining the presence or amount of the analyte, wherein the immobilized binding partner localized in said first zone and the immobilized binding partner localized in said second zone have different affinities for or reactivities to the analyte.