Pleural fluid levels of adenosine deaminase (ADA) have been found to be high in patients with tuberculosis with sensitivity of 91.4%.
Ref: J Clin Lab Anal. 2005;19(2):40-6.

According to a study in China, When the level of ADA was higher than 45 U/L, the sensitivity, specificity and accuracy in the diagnosis of tuberculous ascites were 100%, 97.1% and 98.5%.
Ref:Sichuan Da Xue Xue Bao Yi Xue Ban. 2003 Apr;34(2):320-1.

According to a study in Africa, the median ADA level in the tuberculous pericarditis is 71.7 U/L (range, 10.3 to 303.6 U/L), With a cut off activity of 30 U/L, sensitivity was 94%, specificity was 68%, and positive predictive value was 80%.

Ref: Chest. 2002 Sep;122(3):900-5.

According to a study in India, Mean CSF-ADA levels in TBM patients was 9.61 +/- 4.10 IU/L and was significantly elevated as compared to viral encephalitis and enteric encephalopathy cases; but difference was insignificant in comparison to pyogenic meningitis (7.92 +/- 0.95 IU/L) and cerebral malaria. Hence ADA in CSF may not be reliable for daignosis of TBM.
REf: J Assoc Physicians India. 1999 Feb;47(2):192-4.