Agglutination immunoassay and kit for determination of a multivalent immune species using a buffered salt wash solution.

摘要

A test kit is used in an agglutination immunoassay to determine a multivalent immune species, such as Streptococcus A antigen, in a biological sample. The method includes contacting an aqueous solution of the species with an agglutination indicator reagent having receptor molecules reactive with the species to form an agglutinate of the reaction product of species and receptor. These receptor molecules are bound to polymeric particles which contain tracer molecules. The resulting agglutinate is captured on a microporous membrane which has an average pore size which is at least five times greater than the average diameter of the polymeric particles. Unagglutinated residual materials are washed through the membrane using a wash solution. This solution has a pH of from 5 to 10 and an ionic strength of at least 0.25. Tracer is then determined either in the agglutinate or in the residual materials. The test kit includes the agglutination indicator reagent, the wash solution, and optionally an extraction composition.