Efficacy of adenosine deaminase in the diagnosis of pleural effusions.

Adenosine deaminase (ADA) activity was studied in 53 patients with pleural effusions. Patients with tuberculous pleural effusion (36) had significantly higher ADA activity (77.68 IU/L; P less than 0.001) in comparison to malignant (14.47 IU/L) and parapneumonic (28.65 IU/L) effusions. When tested with a reference limit of over 50.75 IU/L, the specificity of ADA activity was found to be 94.1 per cent. With a sensitivity of 100 per cent, low cost and easy performance pleural fluid ADA activity is proposed as a routine investigation for etiological diagnosis in pleural effusion.