Rapid screening test for tuberculosis using a 38-kDa antigen from Mycobacterium tuberculosis.

A screening test for the diagnosis of tuberculosis by immunodot (IDt) is described, using an antigen of Mycobacterium tuberculosis, namely, a 38-kDa glycoprotein which has shown great specificity in previous serologic analyses. The test was used to examine 28 sera from patients with lung tuberculosis. Of these, 85% were positive by micro-ELISA and by the IDt test herein described. Control sera from healthy subjects (n = 20) gave negative results for ELISA and for IDt, which indicates that the screening test is highly specific. The test is easy to handle and requires no equipment and is therefore particularly useful for field studies.