Hemolysis-in-gel test in immunity surveys and diagnosis of rubella

The hemolysis-in-gel (HIG) technique was adapted for rubella antibody determinations. Use of sucrose gradient purified virus and its coupling with CrCl₃ to chicken erythrocytes resulted in gel plates that could be stored for several weeks and were suitable for reproducible antibody determinations. In a serological survey of young healthy adults the HIG values (range > 2–13 mm) were in close correlation to those obtained by the HI test (> 10 to 320). The HIG test seems well suited for screening the need of vaccination. Seronegative sera (HIG > 2, HI> 10) gave without heat inactivation hemolysis zones ranging from 4 to 6.5 mm. Although the present rubella HIG test did not measure IgM antibodies, the test, by virtue of its accuracy and sensitivity — extending to antibody levels corresponding to HI titers 2–10 — provides a simpler and more rapid means for diagnosis of rubella infections than the conventional HI and CF tests.