Metal sol capture immunoassay procedure, kit for use therewith and

Abstract

Antibody coated gold sol particles and antibody coated solid phase particles dispersed in an aqueous system react immunologically as a function of the presence of an analyte in a sample to be analyzed to produce a collectible, solid phase, gold-containing composite. The composite is collected on a filter or at the bottom of a test tube by centrifugation or gravitation and the analyte in the sample is determined or detected by direct visual examination of the collected solid phase composite which has a pink or red or purplish coloration as a result of the gold contained thereby. The materials required for conducting the assay comprise coated gold particles, coated solid phase particles and a collector element such as a filter. The collected, solid phase, metal-containing composite, which may be directly visually examined to determine or detect the gold therein and thus the analyte in the sample, is stable and remains available for confirmation of test results at a later time.