Patent ID: 8071394

Claim:
A device for determining the presence of an analyte in a liquid sample, the device comprising: a test strip defining a flow path, comprising: a second reagent zone positioned along the flow path, the second reagent zone comprising a first binding agent, the first binding agent being mobilizable by the liquid sample, the first binding agent being capable of binding the analyte to form a first complex; a first reagent zone located downstream of the second reagent zone along the flow path, the first reagent zone comprising a second binding agent, the second binding agent being mobilizable by the liquid sample, the second binding agent being capable of binding the first complex to form a second complex, the second binding agent comprising a detectable label; and a test zone located downstream of the first reagent zone along the flow path, the test zone comprising a third binding agent, the third binding agent being immobilized in the test zone, the third binding agent being capable of binding the first or second complex; wherein the second reagent zone is separable from the first reagent zone, and wherein prior to placing said second reagent zone in fluidic communication with the test strip, the liquid sample has been in contact with the second reagent zone for a period of time sufficient to effect formation of the first complex.