Adenosine deaminase activity and lysozyme levels in children with tuberculosis.

Serum adenosine deaminase (ADA) activity and lysozyme levels were measured in 51 patients with tuberculosis (21 pulmonary, 15 miliary, 11 neurotuberculoma and four abdominal plus osteoarticular) and 20 healthy controls. The mean serum ADA activity and lysozyme levels were significantly raised in children with different forms of tuberculosis in comparison with controls (p < 0.001). The neurotuberculoma cases had the lowest mean enzyme levels and the differences were significant when compared with other forms of tuberculosis. The cut-off serum ADA activity of > or = 42 IU/l and lysozyme level of > or = 20 U/l were diagnostic of tuberculosis with 100 per cent sensitivity. A significant correlation was observed between the two parameters (r = 0.66; p < 0.001). Thus, with compatible clinical presentation, the raised serum level of either ADA or lysozyme can be used as a supportive diagnostic test.