Evaluation of the hemolysis-in-gel test for the screening of rubella immunity and the demonstration of recent infection.

The hemolysis-in-gel method for detection of antibodies to rubella virus gave results which correlated well with results of hemagglutination inhibition and neutralization tests. With a diffusion time of 24 or 48 h, a linear correlation was obtained between the logarithm of antibody concentration and the diameter of the hemolytic zone. Fourfold, and even twofold, differences in serum antibody concentrations were shown to give statistically significant differences in hemolytic zone diameters. It could therefore be concluded that the hemolysis-in-gel test is well suited for the serological diagnosis of primary rubella infection, as well as of reinfection. The sensitivity of the hemolysis-in-gel test was comparable to that of the hemagglutination inhibition test. Pigeon erythrocytes were superior to sheep erythrocytes for use in the test. Studies of the antibody response after natural rubella infection or vaccination showed that the appearance and persistence of antibodies measured by hemolysis in gel is similar to that of hemagglutination inhibition antibodies.