Diagnostic significance of adenosine deaminase in cerebrospinal fluid and blood of tubercular meningitis patients

Introduction: Tubercular meningitis (TBM) remains a major global health problem and is the most dangerous form of extra-pulmonary tuberculosis. Therefore early, simple and inexpensive diagnostic test has always been a matter of concern especially in a developing country like India. Therefore we aimed in our study to find out the diagnostic significance of cerebrospinal fluid (CSF) and blood adenosine deaminase (ADA) in TBM patients with an objective to yield valuable information about its relative sensitivity and specificity in CSF and blood separately. Materials and Methods: A total of 130 participants of both sexes, between 1 to 70 years of age were recruited in this study, out which 80 were diagnosed cases of TBM and 50 were controls. Quantitative estimation of ADA was done in CSF as well as serum samples of the participants by the method of Galanti and Giusti. Results were analysed statistically to arrive at the final conclusion. Observation &Results: CSF as well as serum ADA was found to be statistically significantly higher in cases of TBM as compared to controls. CSF ADA value was 13.95±3.91 IU/L in cases and 6.05±2.37 IU/L in controls (p<0.001) whereas serum ADA value was 71.96±16.33 IU/L in cases and 25.85±10.49 IU/L in controls (p<0.001). Further, at the cut off value of 9IU/L for CSF ADA, the sensitivity was 91.25% in tubercular meningitis patients. Conclusion: Our study gave supportive evidence that CSF ADA is a sensitive, rapid and economical test for the early diagnosis of TBM while the levels of ADA in blood cannot be used as a diagnostic tool for TBM.