Patent ID: 7285424

Claim:
A membrane-based assay device for detecting the presence or quantity of an analyte residing in a test sample, the device comprising: detection probes that comprise non-magnetic particles conjugated with a first specific binding member and labeled with a detectable luminescent substance that is configured to emit a detection signal, the first specific binding member being capable of binding with the analyte; calibration probes that comprise magnetic particles conjugated with a second specific binding member and labeled with a detectable luminescent substance that is configured to emit a calibration signal that is distinguishable from the detection signal, the second specific binding member being capable of binding with the analyte; a porous membrane in fluid communication with the detection probes and the calibration probes, wherein the porous membrane defines a detection zone; and a magnetic device positioned adjacent to the detection zone, the magnetic device being configured to immobilize the calibration probes within the detection zone, the magnetic device further being configured to immobilize within the detection zone complexes formed from the detection probes, the analyte, and the calibration probes.