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 less than 2--13 mm) were in close correlation to those obtained by the HI test (less than 10 5o 320). The Hig test seems well suited for screening the need of vaccination. Seronegative sera (HIG less than 2,HI less than 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.