Evaluation of a Serological Test for the Diagnosis of Tuberculosis Using the 38KDa Antigen

Abstract

Objective: To evaluate an enzyme immunoassayutilising the 38 KDa Mycobacterial antigen as a pos-sible test for the laboratory diagnosis of tuberculosis.Method: The sera of 37 patients with confirmed tuber-culosis, 37 tuberculin-negative, apparently healthy in-dividuals and 27 tuberculin-positive, apparently healthyindividuals were tested. Moreover, seropositive, appar-ently healthy individuals were tested by a peripheral-blood-based PCR assay using a broad range bacterialprimer and one that is specific for the M. tuberculosiscomplex.Results: Four of 37 patients with confirmed tuberculo-sis, 10 of 37 tuberculin-negative, apparently healthyindividuals and none (0 of 27) of the tuberculin-posi-tive, apparently healthy individuals were seropositive.All seropositive, apparently healthy individuals werenegative by PCR.Conclusion: The sensitivity of the enzyme immunoas-say utilising the 38 KDa antigen in this study was 10.8%and the specificity 84.4%. Thus, it appears that this testmay not be used for the diagnosis of tuberculosis inthe Lebanese.Key words: Tuberculosis, enzyme immunoassay, 38 KDaantigen, PCR.