A modified passive-haemagglutination technique for the detection of cytomegalovirus and herpes simplex virus antibodies: application in virus-specific IgM diagnosis.

Cytomegalovirus (CMV) and herpes simplex virus (HSV) antibodies were detected by a modified passive haemagglutination (PHA) technique. The main features of this modification are the use of a simpler method for the removal of nonspecific sheep agglutinins in the sera, the deployment of commercially available CMV and HSV antigens, and a different sucrose density gradient (SDG) system for the separation of IgM from IgG. The modified procedure proved to be a reliable, specific, and sensitive technique in detecting antibodies to CMV and HSV in both whole serum and in the separated IgM and IgG fractions. It was as reliable as the complement-fixation (CF) test when applied in seroepidemiological studies and in the detection of antibodies in cord serum. Preliminary data are provided which suggest that the combination of SDG and PHA may prove to be a more reliable system for the detection of exclusion of CMV-specific IgM than an enzyme-linked immunosorbent assay (ELISA).