A gelatin particle agglutination (PA) assay for detecting serum antibody to cytomegalovirus (CMV-Ab) was established. CMV antigen extracted from CMV infected human embryonic lung fibroblast (HEL) cells was coated on gelatin particles. These particles were mixed with diluted test serum in 96 well round bottom microtiterplates. After 2h incubation at room temperature, the positivity of test serum was judged by the sedimented pattern of agglutinated particles in the wells. The sensitivity and the positivity of this PA were compared with an enzyme immunoassay (EIA) and a latex agglutination (LA) assay. The results of the PA assay were well coincident with those of the EIA. On the other hand, the LA assay was less sensitive than the PA assay and the EIA. These results indicated that the PA assay had good specificity and sensitivity for the detection of CMV-Ab in sera. Furthermore, simplicity of the PA assay was considered to be advantageous for the mass screening of blood donors. A total of 2553 blood donors were tested using PA assay at Aichi Blood Center. The CMV-Ab positive rate was 85%, and the positive rate increased with age (18-20 y. o. 61%; 61-64 y. o. 100%).
