Diagnostic value of enzyme linked immuno-sorbent assay for cytomegalovirus disease

Since interpretation of results of enzyme linked immuno-sorbent assay (ELISA) for diagnosis of Cytomegalovirus (CMV) infection in India is difficult, its diagnostic value required evaluation.

To evaluate the diagnostic value of ELISA against polymerase chain reaction (PCR) in CMV disease.

Results of ELISA test for CMV antibodies in CMV-DNA PCR positive and negative patients and normal healthy blood donors were analysed.

Anti-CMV antibodies were assayed by ELISA on the sera of 26 CMV PCR positive and 21 PCR negative patients and 35 normal healthy blood donors.

Chi square and Fischer exact test were used for statistical analysis.

Anti-CMV antibodies (IgG or IgG and IgM) were present in 20 (76.9%) of 26 PCR positive and 13 (61.9%) of 21 PCR negative patients. ELISA was negative in six (23.1%) of 26 PCR positive patients. Of the 28 paediatric patients, ELISA was positive in 14 (73.7%) of 19 PCR positive and three (33.3%) of nine PCR negative patients showing a statistically significant difference (Chi square test, P value 0.038). Among the 19 patients having complications after organ transplant, ELISA showed anti-CMV antibodies in six (85.7%) of seven PCR positive and 11 (91.7%) of 12 PCR negative patients showing no significant difference. CMV-DNA was not detected in the buffy coat of 35 sero-positive blood donors.

ELISA has no diagnostic value in the detection of CMV activation although it may help in the differential diagnosis of CMV infection in the paediatric age group.