Abstract: Disclosed is a device and method of use for detecting polyvalent analytes such as antibody to the AIDS virus, utilizing an inverse sandwich method. The test device comprises a first substance having an epitope, bound to a label and capable of moving within the test device. The test device further comprises a second substance immobilized to the test device and spatially separated from the first substance. The second substance has an epitope substantially similar to the epitope of the first substance. Upon application to the test device, the polyvalent analyte binds to the first substance and moves within the test device to the location of the second substance with both polyvalent analyte and first substance are immobilized at location of the second substance. Polyvalent analyte is detected by the presence of the label at the location of the second substance. Also disclosed is a control substance for use with the device that can be used to determine completion of the test and viability of the device.