Performance of Adenosine Deaminase assay in diagnosis of pulmonary & extrapulmonary tuberculosis

There has been a lot of debate about the use of the Adenosine Deaminase (ADA) for tuberculosis (TB) diagnosis. In the present study, to overcome this debate, we have planned a large scale study in all forms of TB to access the performance of ADA for diagnosis of TB. we have also studied the performance of the ADA in the Tb prognosis. ADA activity was evaluated using Guisti and Galanti method. The sensitivity of the ADA test is impressive in all forms of TB clinical samples analysed for the study (PTB [82%], TBM [85%] TBAR [85%]), and (ATB) [84%]. However, the specificity was variable in pulmonary TB, but satisfactory in extrapulmonary TB (EPTB) cases (i.e TBM [89%], (ATB) [88%], TBAR [88%]). In the follow-up samples, ADA value declined drastically after the anti TB medication (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. We recommend, ADA test is quite useful for EPTB diagnosis along with other clinical correlations and in absence of other advanced diagnostic tests. However, on the other ADA can be used as a prognostic test for all forms of TB.