Modified hemagglutination-inhibition test for rubella employing human group O erythrocytes

A hemagglutination-inhibition (HI) test for rubella is described which utilizes human group O, rather than 1-day-old chick, erythrocytes. The test was found to be as sensitive and reproducible for detection of rubella antibody as HI tests employing chick erythrocytes. Advantages to the use of human erythrocytes are (i) they are more available, (ii) it is unnecessary to absorb natural agglutinins from human test sera, and (iii) heparin-MnCl(2)-treated sera do not agglutinate human erythrocytes, as is sometimes the case with chick erythrocytes. Factors influencing the reliability of the test are discussed.