Improvement of the indirect hemagglutination assay for Salmonella typhi Vi antibodies by use of glutaraldehyde-fixed erythrocytes.

Glutaraldehyde-fixed sheep erythrocytes sensitized with Vi antigen were shown to be usable for at least 1 year in the indirect hemagglutination assay for Vi antibodies. The use of fixed sensitized erythrocytes improves the practicality of the indirect hemagglutination assay by (i) eliminating the need to sensitize cells each time the test is performed; (ii) reducing waste of the purified Vi antigen; and (iii) reducing test-to-test variation.