Diagnostic utility of ELISA test using antigen A60 in suspected cases of tuberculous meningitis in paediatric age group.

The aim of the study was evaluation of the utility of ELISA test using antigen A60 for rapid diagnosis of tuberculous menigitis (TBM) in paediatric age group. ELISA test based on mycrobacterial antigen A60 (Anda biological, France) was used to estimate specific IgM and IgG antibodies in the sera and CSF of 20 suspected cases of TBM which were selected on the basis of numerous parameters and were smear negative on concentrated smear of CSF. Sera of 20 Montoux negative healthy children was taken as control by detecting IgM and IgG antibodies to A60 antigen. Response to anti-tubercular treatment was observed in all the suspected cases of TBM. This study showed that specificity for diagnosis of TBM by detecting IgM and IgG antibodies in sera was 90% and 80% respectively. Sensitivity of the test by detecting IgM and IgG antibodies in sera was 85% and 80% respectively with positive predictive value of 89.47% for IgM antibody and 80% for IgG antibody. In CSF IgM and IgG antibodies were found in 75% and 60% cases respectively. Both were positive only in 60% of cases. It is concluded from this study that 80-85% cases of TBM in paediatric age group have eigher IgM or IgG antibodies in sera whereas 60-75% have antibodies in CSF.