Serodiagnosis of intestinal tuberculosis by the soluble antigen fluorescent antibody test (SAFA test)

The diagnosis of intestinal tuberculosis can only be established by the tissue obtained during surgery or endoscopy. We investigated the role of the soluble antigen fluorescent antibody (SAFA) test with the possibility that it may prove to be a valuable technique for the serodiagnosis of intestinal tuberculosis. The sera of 38 patients and 60 control subjects were studied. Mycobacterial saline extract was used as an antigen in the test. Thirty-two (84%) of 38 patients with intestinal tuberculosis yielded positive values (fluorescence coefficient greater than 3). Among the control subjects a false positive result was observed in only one patient who had eosinophilic enteritis. Patients with intestinal tuberculosis had a significantly higher level of antibodies than patients with non-tuberculous intestinal disease and healthy subjects. These results suggest that this technique may be used for the diagnosis of intestinal tuberculosis and in differentiating it from other non-tuberculous intestinal diseases.