Abstract: Analytical test kits and assay procedure employs test cards or strips of an inert plastic carrier having a flat, non-absorbent surface, containing thereon spots of insolubilized reagent for the determination of an analyte, such as an antigen or an antibody, in a liquid medium such as serum or other body fluids in a solid phase enzyme immunoassay of the sandwich type. Different binding partners can be placed as separate spots on the same card for the assay of a group of related or unrelated analytes in the same test sample. An insoluble colored product on a spot, qualitatively and quantitatively, is indicative of a positive result.