Serodiagnosis of extra pulmonary tuberculosis using A-60 antigen

The diagnosis of extrapulmonary tuberculosis including neurotuberculosis is difficult because of the low yield of culture positivity for Mycobacterium tuberculosis (M. tb). Serodiagnosis has emerged as a useful aid to the diagnosis of extrapulmonary tuberculosis. The utility and efficacy of detection of antimycobacterial antibodies to A-60 antigen in serum and/or cerebrospinal fluid (CSF) was analysed in 100 patients-neurotuberculosis-72, abdominal tuberculosis-12 and others-16. The overall positivity rate for the test was 75%. The positivity rate of the test in serum and/or CSF was 79.2% (57 of 72) in neurotuberculosis and 62.5% (10 of 16) for other forms of extrapulmonary tuberculosis. The positivity rate for antimycobacterial antibodies was higher for patients with tubercular meningitis -94.7%. To conclude, testing for antimycobacterial antibodies to A-60 antigen is a useful adjunct in the diagnosis of extrapulmonary tuberculosis especially neurotuberculosis.