An enzyme immunoassay for the detection of IgM antibodies to rubella virus in serum. Purified Rubella antigen is coated on the surface of microwells. Diluted serum is added to the wells, and the Rubella IgM- specific antibody, if present, binds to the antigen during incubation. After washing the wells to remove unbound sample, antibody to human IgM conjugated with horseradish peroxidase (HRP) is added and incubated at 37°C for 30 minutes. Unbound conjugate is removed by a subsequent washing step. A solution of TMB Reagent is then added to the microwells. The enzyme conjugate catalytic reaction is stopped at a specific time. The intensity of the color generated is proportional to the amount of IgM-specific antibody in the sample. The results are read by a microwell reader compared in a parallel manner with calibrator and controls.