A method for the determination of the concentration of an analyte in a liquid sample comprising: a) contacting the sample with a labeled receptor to form a mobile phase, the labeled receptor characterized by an ability to bind to the analyte to provide, in the mobile phase, a labeled receptor-analyte complex; b) contacting the mobile phase with a first test area on a solid support, the solid support characterized in that labeled receptor can provide a detectable signal when bound thereto, the solid support configured to allow the mobile phase to flow from the first test area to a second test area and from the second test area to a control zone, the first test area comprising a first test area capture agent, the first test area capture agent characterized in that the capture agent has greater binding affinity to the labeled receptor than to the labeled receptor-analyte complex; c) allowing the mobile phase to flow from the first test area to the second test area and from the second test area to the control zone, the second test area comprising a second test area capture agent characterized in that the capture agent has greater binding affinity to the labeled receptor than to the labeled receptor-analyte complex, the second test area capture agent being the same capture agent as the first test area capture agent, the control zone comprising a control zone capture agent characterized in that the control zone capture agent has equivalent affinity to the labeled receptor and the analyte-labeled receptor complex; d) measuring the intensity of the signals at the first test area, the second test area and the control zone, wherein the intensity of the signals in each of the test areas are inversely related to the concentration of analyte in the sample. a) contacting the sample with a labeled receptor to form a mobile phase, the labeled receptor characterized by an ability to bind to the analyte to provide, in the mobile phase, a labeled receptor-analyte complex; b) contacting the mobile phase with a first test area on a solid support, the solid support characterized in that labeled receptor can provide a detectable signal when bound thereto, the solid support configured to allow the mobile phase to flow from the first test area to a second test area and from the second test area to a control zone, the first test area comprising a first test area capture agent, the first test area capture agent characterized in that the capture agent has greater binding affinity to the labeled receptor than to the labeled receptor-analyte complex; c) allowing the mobile phase to flow from the first test area to the second test area and from the second test area to the control zone, the second test area comprising a second test area capture agent characterized in that the capture agent has greater binding affinity to the labeled receptor than to the labeled receptor-analyte complex, the second test area capture agent being the same capture agent as the first test area capture agent, the control zone comprising a control zone capture agent characterized in that the control zone capture agent has equivalent affinity to the labeled receptor and the analyte-labeled receptor complex; d) measuring the intensity of the signals at the first test area, the second test area and the control zone,