Rapid method to detect rubella immunoglobulin M and immunoglobulin A antibodies

Immunoglobulin (Ig) G was removed from serum specimens by precipitation with gamma chain-specific anti-human IgG of rabbit origin. The remaining rubella virus-specific IgM (and IgA) antibodies were then detected by the rubella hemagglutination-inhibition test. This procedure has proven to be as reliable as estimations carried out with IgM fractions separated on a sucrose density gradient.