Comparison of the Enzyme-linked Immunosorbent Assay and the Indirect Hemagglutination Test for Detection of Antibody to Cytomegalovirus

Thirty samples of serum were tested for antibody to cytomegalovirus by enzyme-linked immunosorbent assay (ELISA) and indirect hemagglutination (IHA). The two tests were in extremely close agreement. Of the 30 sera evaluated by ELISA, 16 were considered to be positive and 14 were considered negative. In all 16 positive samples, the titers by ELISA were at least twofold to 10-fold higher than the indirect hemagglutination titers. Two of the 14 sera evaluated as negative by the ELISA test had low indirect hemagglutination titers (1:8 and 1:4). They were not detectable at the initial dilution (1:50) of the ELISA test. These two sera might have been classified as positive if the initial dilution in ELISA had been lower than 1:50.