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Adenosine Deaminase (ADA) estimation in all forms of tuberculosis (TB) is done by several investigators, however, there has been a lot of debate about the use of the ADA for TB diagnosis. In the present study, to overcome this debate, we have planned a large scale study in the Central India population for all forms of TB i.e. pulmonary TB (PTB), tuberculous meningitis (TBM), TB arthritis (TBAR), and abdominal tuberculosis (ATB) to access the performance of ADA for diagnosis of TB. In addition to that, we have also studied the performance of the ADA test in the prognosis of TB. ADA activity was evaluated using the method of Guisti and Galanti. To evaluate the role of the ADA test as a prognostic marker in TB, we have collected follow-up clinical samples of PTB and TBM cases. The sensitivity of the ADA test is impressive in all forms of TB clinical samples analyzed for the study (PTB [82%], TBM [85%] TBAR [85%]), and (ATB) [84%]. However, the specificity was variable as ADA test results were found to be satisfactory for extrapulmonary TB (EPTB) cases ( i.e TBM [89%], (ATB) [88%], TBAR [88%]), on the other hand, poor specificity was observed in PTB cases (PTB [48%]). In the follow-up clinical samples (collected before and after anti-TB treatment [ATT]). In the follow-up samples, the result of the ADA test was observed to have declined drastically thereby showing a negative value after the ATT. Our study, which consists of a large number of samples, suggests that the ADA has very limited value in the diagnosis of PTB, and hence it is not recommended for PTB diagnosis. On the other hand, the ADA test is found to be useful for the diagnosis of EPTB in correlation to the patient's clinical condition. Along with the above-mentioned aspects and according to our follow-up study results, we recommend that ADA be useful as a prognostic indicator for TB.

Introduction: Various serological assays exists, including Antigen and Antibody detection (IgM and IgG) for diagnosis of Tuberculous Meningitis (TBM) cases. To the best of our knowledge, most of the laboratories either do Antigen detection or IgM or IgG, at a time. As different antigens get expressed in a different stage of infection it may be possible that many cases remain undiagnosed due to one test at a time approach. Aim: To evaluate the combination of Mycobacterium Tuberculosis (MTB) antigen (Ag85 Complex and Rv2623) and antibody (Anti-Ag85, Anti-45kD, Anti-HSP-16, Anti-CFP-10 Anti-GroES and Anti-ESAT-6) immunoassay panels in the Cerebrospinal Fluid (CSF) samples for diagnosis of TBM patient. Materials and Methods: In the present prospective study conducted at Central India Institute of Medical Sciences (CIIMS) from October 2013 to April 2015, a total of 200 CSF samples of different groups {confirmed TBM (n=100) and noninfectious neurological diseases as control (n=100)} were analysed by Enzyme-Linked Immunosorbent Assay (ELISA). A panel of MTB antigens consisting of Ag85B, 45kDa, HSP-16, CFP-10, GroES and ESAT-6 were used for detection of antibodies response, whereas polyclonal antibodies were used for antigen detection of Ag85 complex and Rv2623 in the CSF samples. The comparison of the CSF parameter between TBM and non-TBM patients was performed using a student t-test. A p-value <0.05 was considered statistically significant for all the analyses. Results: The study population has similar age and sex distribution (p>0.05). Symptoms of headache, fever, neck stiffness, vomiting, abnormal behaviour, unconsciousness were more common among the TBM patients as compared to non-TBM patients (p<0.05) (TBM Vs non-TBM). Similarly TBM patients had an increase (p<0.05) Vs non-TBM total cell count, protein, parallel blood sugar and decline in CSF sugar and Parallel blood sugar ratio (p<0.05) (TBM Vs non-TBM). We found diagnostic accuracy of 67% to 76% with either antigen or antibody assay, however, combinations of antigen and antibody immunoassay together increase the diagnostic accuracy of up to 96%. Conclusion: Our study recommends that a combination of antigen and antibody assay should be considered for early and accurate diagnosis of TBM cases.