A modified rubella HI test using prestandardized reagents.

A modified haemagglutination inhibition test for rubella antibodies using prestandardized freeze-dried reagents was compared to a "standard" method. Tests of 707 serum samples showed that the modified test was sensitive and reliable by both macrotitration and microtitration techniques. The minor disadvantages of some reduction in antibody level when rubella sera were tested within one week of the rash and of spontaneous sheep erythrocyte agglutination in 0-7% of sera were out-weighed by the increased speed of the new test and the fact that it was carried out at room temperature.