The value of adenosine deaminase (ADA) determination in the diagnosis of tuberculous ascites

In order to evaluate the role of the determination of adenosine deaminase activity (ADA) in ascitic fluid for the diagnosis of tuberculosis, 44 patients were studied. Based on biochemical, cytological, histopathological and microbiological tests, the patients were divided into 5 groups: G1-tuberculous ascites (n = 8); G2-malignant ascites (n = 13); G3-spontaneous bacterial peritonitis (n = 6); G4-pancreatic ascites (n = 2); G5-miscelaneous ascites (n = 15). ADA concentration were significantly higher in G1 (133.50 +/- 24.74 U/l) compared to the other groups (G2 = 41.85 +/- 52.07 U/l; G3 = 10.63 +/- 5.87 U/l; G4 = 18.00 +/- 7.07 U/l; G5 = 11.23 +/- 7.66 U/l). At a cut-off value of > 31 U/l, the sensitivity, specificity and positive and negative predictive values were 100%, 92%, 72% and 100%, respectively. ADA concentrations as high as in tuberculous ascites were only found in two malignant ascites caused by lymphoma. We conclude that ADA determination in ascitic fluid is a useful and reliable screening test for diagnosing tuberculous ascites. Values of ADA higher than 31 U/l indicate more invasive methods to confirm the diagnosis of tuberculosis.