Diagnostic Value of Adenosine Deaminase in Tuberculous Pericarditis

Because of the difficulty in isolating the causative organism, the diagnosis of pericardial tuberculosis is often doubtful. Adenosine deaminase (ADA) activity was measured in the pericardial fluid of 108 patients of undetermined origin. The causes of pericardial fluid fell into 5 groups: I. tuberculosis (20 cases), II. idiopathic (82 cases, III. neoplasia (3 cases), IV. purulent bacterial infection (2 cases) and V. radiotherapy (1 case). A tuberculous etiology was diagnosed by bacterial examination of the pericardial fluid (4 cases), histologic study of the pericardium (2 cases), presence of associate active extracardiac tuberculosis (9 cases) and good response to antituberculous treatment (5 cases). The highest mean ADA value (126±16.68 u/l) was found in group I. which in other groups values were 29.4±8.9, 27.7±2, 29.5±13.4, 26 u/l, respectively. There was a statistically significant difference in this respect between group I and the other groups (p<0.001). When 70 u/l was taken as discriminant value for the diagnosis of tuberculous pericarditis, then the adenosine deaminase value had a 100 percent sensitivity and 91 percent specificity. Measuring the pericardial concentration of adenosine deaminase therefore is a helpful procedure in the diagnosis of tuberculous pericarditis.