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 neurotubercu loma and four abdominal plus osteoarticular) and 20 healthy controls. The m ean serum ADA activity and lysozyme levels were significantly raised in chi ldren with different forms of tuberculosis in comparison with controls (p < 0.001). The neurotuberculoma cases had the lowest mean enzyme levels and t he differences were significant when compared with other forms of tuberculo sis. The cut-off serum ADA activity of greater than or equal to 42 IU/I and lysozyme level of greater than or equal to 20 U/I were diagnostic of tuber culosis with 100 per cent sensitivity. A significant correlation was observ ed 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.