Tuberculosis is one of the commonest chronic infectious diseases, which is highly endemic in India. It usually affects lungs but cases of extra pulmonary tuberculosis are not rare. In a large percentage of cases, involvement of pleura, peritoneum, meninges and synovial membranes is also common. Pulmonary tuberculosis can be confirmed by sputum examination and diagnosed easily, but diagnosing extra pulmonary TB becomes frequently difficult since the specificity and sensitivity of non – invasive methods is low. Adenosine deaminase (ADA) has been proposed to be useful surrogate marker for tuberculosis in pleural, pericardial, peritoneal fluids and cerebrospinal fluid (CSF).

Objective

The aim of the study is to assess the diagnostic value of ADA in extra pulmonary tuberculosis.

Materials and Methods

The study was carried out during the period of October, 2015 to June, 2016 on 100 patients suffering from serosal effusion (50 pleural, 30 peritoneal and 20 samples of CSF). Detailed clinical history, physical examination and routine and relevant investigation of all patients including ADA estimation by Galanti and Guisti method was done.

Results

Out of 100 patients of serosal effusion, 43 were of tubercular and 57 of non–tubercular etiology. ADA level in tuberculous pleural effusion ranged from 43.0 –187.9 U/L with a mean level of 102.0 U/L. ADA level in tubercular peritoneal effusion ranged from 41.5 – 246 U/L with a mean level of 105.8 U/L. ADA level in CSF from tuberculosis meningitis patients ranged from 11.5 – 77.0 U/L with a mean level of 29.6 U/L. Overall serosal fluid ADA estimation offers high degree of sensitivity and specificity of about 98% and 95% respectively.

Conclusion

The method of ADA estimation is easy, simple and doesn’t require expensive equipment. The present study shows that a simple, inexpensive, highly sensitive and specific test like ADA estimation should be employed as a marker to diagnose extra pulmonary tuberculosis.