Enzyme-linked immunosorbent assay (ELISA) for HIV antibody by a glass slide technique

An enzyme-linked immunosorbent assay (ELISA) technique is described which utilizes a commercially available glass microscope slide coated with hydrophobic teflon in such a pattern as to give 30 small circular wells, each of which has a glass bottom. Each well serves as a solid phase, analogous to a microtiter well for adsorption of purified human immunodeficiency virus (HIV) antigens. Since only 5-10 microliter volumes of reagents are used and rinsing processing is simple, the cost per test is much less than most other ELISA technologies. HIV antigen is stable for over 1 year at 37 degrees C when dried on the glass slides. The sensitivity and specificity of the micro slide immunoenzymatic assay (Micro-SIA) was studied by testing randomly selected, known HIV-seropositive and seronegative plasma. Results compare well with microtiter and Western blot assays. A simple vertical-beam colorimeter is described (useful in the Micro-SIA) which can be easily assembled by the user from commonly available components.