Abstract: A multiwell apparatus for the assay of microliter quantities of body fluids is provided which prevents fluid loss by lateral migration or gravity flow through a microporous membrane or ultrafilter. A sample is passed through a membrane to which an antibody has been bonded in order to harvest complementary viral antigens in the sample. The harvested viral antigen is converted to single strand DNA or RNA which then is deposited on a second membrane. The deposited single strand DNA or RNA is capable of reacting with labeled DNA or other suitable detection probe which can be detected and correlated with antigen concentration in the sample.

Abstract: A test device for assaying liquid samples for the presence of a predetermined reagent is described. The device comprises telescoping top and bottom members defining a liquid reservoir therebetween, resilient means for biasing the members in the open position, one or more test wells in the top member with bottom openings covered with microporous membranes, a co-reactant immobilized on the membrane surfaces, and sorbent means between the members spaced from the membrane(s) in the open position but in contact therewith in the closed position. Liquids are passed through the membrane(s) into the sorbent means by depressing the members to the closed position.