[Escherichia-erythrocyte diagnostic agents]

The conditions of a simple and practicable method for the preparation of effective antigenic nonprotein diagnosticums on the basis of water-phenol extracts of 23 Escherichia species have been developed. The method consists in heating the mixture of erythrocytes and the antigen in a boiling water bath for 60 minutes. The diagnosticums thus obtained are 16-30 times more sensitive in the passive hemagglutination test and 4-6 times more sensitive in the passive hemagglutination inhibition test than diagnosticums prepared with the use of tannin, rivanol, as well as by the common method for the preparation of nonprotein antigens. The minimum concentration of Escherichia cells detected in the passive hemagglutination inhibition test is 0.8-1.2 million cells/ml.