Evaluation of a serological test for the diagnosis of tuberculosis using the 38kda antigen

To evaluate an enzyme immunoassay utilising the 38 KDa Mycobacterial antigen as a possible test for the laboratory diagnosis of tuberculosis. Method: The sera of 37 patients with confirmed tuberculosis, 37 tuberculin-negative, apparently healthy individuals and 27 tuberculin-positive, apparently healthy individuals were tested. Moreover, seropositive, apparently healthy individuals were tested by a peripheralblood- based PCR assay using a broad range bacterial primer and one that is specific for the M. tuberculosis complex. Results: Four of 37 patients with confirmed tuberculosis, 10 of 37 tuberculin-negative, apparently healthy individuals and none (0 of 27) of the tuberculin-positive, apparently healthy individuals were seropositive. All seropositive, apparently healthy individuals were negative by PCR. Conclusion: The sensitivity of the enzyme immunoassay utilising the 38 KDa antigen in this study was 10.8% and the specificity 84.4%. Thus, it appears that this test may not be used for the diagnosis of tuberculosis in the Lebanese.