Patent ID: 8900881

Claim:
An assay device for the quantitative determination of an analyte in a sample, comprising a test strip containing a porous test membrane allowing for capillary flow of the analyte, a porous upstream membrane in fluid connection with and located upstream from the test membrane and a porous downstream membrane in fluid connection with and located downstream from the test membrane, wherein: (a) the test membrane containing a test site having immobilized thereon a ligand capable of reacting with the analyte and binding the analyte to the test site, a first standard band having immobilized thereon a first calibrator agent, corresponding to a first known concentration of analyte, a second standard band having immobilized thereon a second calibrator agent corresponding to a second known concentration of analyte, and a third standard band having immobilized thereon a third calibrator agent corresponding to a known third concentration of analyte, wherein each of the first, second and third calibrator agents are capable of reacting with different label conjugates and binding the label conjugates to the first, second and third standard band sites to produce a measurable response, (b) the upstream membrane having a sample application site to which the sample is applied, and having a label conjugate site downstream from the sample application site having the different labeled conjugates deposited thereon, and (c) the downstream membrane capable of absorbing the sample and providing the capillary flow for the sample through the upstream membrane and the test membrane.