Comparative trial of six methods for the detection of CMV antibody in blood donors.

Six techniques were compared to find the most suitable method for determining the cytomegalovirus (CMV) antibody status of blood donors. Five hundred and ninety-six random sera were tested by immunofluorescence (IF), complement fixation (CFT), two enzyme linked immunosorbent assays (ELISA), a commercial indirect haemagglutination test (IHA)--used as supplied, and a locally devised micromodification of the same IHA test. Five hundred and thirty-five sera shared total agreement of results by all tests. The ELISA tests were the most discordant with other methods (10.5% discordancies both positive and negative). IF and CFT correlated well with other tests (0.8% discordances each) but for different reasons are unsatisfactory for donor screening. The IHA test used as supplied and its micromodification gave the most consistent results (0.8% and 0.5% discordancies respectively). The micromodification is easy to perform and read; it compares very favourably with CFT and IF for material costs and expertise required, and readily lends itself to the testing of large numbers of sera in a reasonable time. Within certain provisos the micro-IHA technique described is recommended as the most suitable test for blood donor screening.