Device and method for simultaneously performing multiple competitive immunoassays

A device for simultaneously performing a plurality of competitive immunoassays to provide a positive readout for the presence of respective monoepitopic analytes in a sample, the device comprising a unitary bibulous material providing one or more flow paths, each flow path comprising:

• (a) a common origin site on the bibulous material for the simultaneous application of a fluid sample,
• (b) a plurality of respective reagent zones downstream from the origin site, the reagent zones of each immunoassay providing the reagents necessary for performing a visual read-out, competitive immunoassay for the presence of the respective analyte, the zones comprising, in order and in the direction of flow:
• (i) a competition zone comprising a detectable analyte-conjugate composed of analyte and label, and a first binding partner for the analyte, both being diffusively positioned in such a manner that any free analyte present in the sample is capable of binding to the first binding partner in a competitive manner with the analyte conjugate;
• (ii) a retention zone comprising an excess amount of a second, nondiffusively bound reagent capable of binding to free or bound first binding partner in order to remove it from continued flow in the flow path;
• and
• (iii) a read out zone comprising nondiffusively bound receptor capable of binding in a detectable manner to the analyte-conjugate but not capable of binding to unconjugated analyte.