Evaluation of enzyme-linked immunosorbent assay using mycobacterial saline-extracted antigen for the serodiagnosis of abdominal tuberculosis.

The efficacy of enzyme-linked immunosorbent assay (ELISA) was evaluated in the sera of 215 individuals as a diagnostic aid in abdominal tuberculosis. The subjects had abdominal tuberculosis (group 1), intestinal disorders other than tuberculosis (group 2), cirrhosis of the liver (group 3), and peritoneal malignancy (group 4). Sera from patients of pulmonary tuberculosis and healthy volunteers (group 5) were also analyzed for enzyme activity and served as positive and negative controls. In patients with abdominal tuberculosis, the absorbance (OD) values were significantly higher than for the other groups and healthy volunteers (p less than 0.001). OD values were similar in abdominal and pulmonary tuberculosis (p greater than 0.05). Level above 0.7 (OD) in serum suggests tuberculosis with a sensitivity of 81%, specificity of 88%, and a diagnostic accuracy of 84%. These results suggest that ELISA may be used for the diagnosis of abdominal tuberculosis and in differentiating it from other nontuberculous abdominal diseases.