Evaluation of a rubella hemagglutination inhibition test system

Two systems for measurement of rubella hemagglutination inhibition antibodies were compared. One had chick erythrocytes as indicator and the other, which is available in kit form ("Rubindex," Ortho-Diagnostics), uses human group O erythrocytes. Correlation to within one dilution of each other was noted in 92% of the tests. The Rubindex system has the advantage of longer shelf life of reagents and also does not require one of the absorption steps necessary for the other method, thus saving technologist's time.