The detection and avoidance of false-positive reactions in tests for rubella-specific IgM

Serum specimens tested for rubella-specific IgM by the haemagglutination-inhibition technique may give false-positive results due to (a) storage at -20 degrees C, (b) bacterial contamination, or (c) inactivation at 56 degrees C. These false-positive reactions can be distinguished from rubella-specific IgM activity by their resistance to 2-ME.