[Noninstrumental immunoanalysis based on dyed polyacrolein latexes. Determination of a group-specific polysaccharide from Streptococcus pyogenes].

Non-instrumental immunoassays based on immunofiltration and microtiter particle agglutination (MPA) techniques have been developed using coloured polyacrolein latex. These methods have been applied to the quantification of the group-specific polysaccharide (PS) of S. pyogenes (group A streptococcus) and compared with standard ELISA tests. The most efficient method was MPA; as little as 0.05 ng A-PS/ml could be detected in 1.5 h. In comparison with ELISA test, the sensitivity of MPA was 10 times higher and the procedure was much simpler. The sensitivity of immunofiltration assay using both enzyme and latex conjugates was shown to be the same (50 ng/ml A-PS) and the duration of the assay 3-5 min. No cross-reactions of latex conjugates with non A streptococcus cell lysates have been observed. The developed methods are rapid, robust, easy to perform, don't need any sophisticated equipment and specially trained staff.