Ascitic fluid y interferon concentrations and adenosine deaminase activity in tuberculous peritonitis

The y interferon (,y-IFN) concentration and the adenosine deaminase (ADA) activity were evaluated in 30 patients with tuberculous peritonitis, 21 patients with ascites due to a malignant disorder, and 41 patients with cirrhosis. The y-IFN concentrations were significantly higher (p<0.0001) in tuberculous peritonitis patients (mean: 6-70 U/ml) than in the malignant (mean: 3.10 U/ml) and cirrhotic (mean: 3.08 U/ml) groups. Use of a cut offvalue of ¢3.2 U/mli gave the assay a sensitivity of93% (25 of27), a specificity of 98% (54 of 55), positive (P+) and negative (P-) predictive values of 96% and a test accuracy of 96%. The ADA activity was significantly (p<0-0001) higher in the tuberculous peritonitis group (mean: 101.84 U/i) than in the control groups (cirrhosis (mean: 13-49 U/I) and malignancy (mean: 19.35 U/i)). A cut offvalue of >30 U/l gave the ADA test a sensitivity of 93% (26 of 28) a specificity of 96% (51 of 53), a (P+) value of 93%, a (P-) value of 96%, and a test accuracy of 95%. There was a significant (p<0-0001) correlation (r=0.72) between ADA activity and -y-IFN values in patients with tuberculous peritonitis. These results show that a high concentration of y-IFN in ascitic fluid is as valuable as the ADA activity in the diagnosis of tuberculous peritonitis. Both are rapid non-invasive diagnostic tests for tuberculous peritonitis. (Gut 1995; 36: 419-421)