[Usefulness of IgG and IgM detection against antigen 60 in the diagnosis of thoracic tuberculosis]

We conducted a prospective study in order to assess the use of the "ELISA" method (Anda-Tb) for the detection of antibodies IgG and IgM against antigen 60 in mycobacterias for the initial diagnosis of thoracic tuberculosis. 215 serum samples from 44 patients with tuberculosis and 171 control cases were studied. The threshold value for IgG in our environment is 200 U, resulting in a specificity of 98% and a sensitivity of 34%. The IgM test has a low sensitivity, although when combined with the IgG, the sensitivity of the test increases while its specificity is reduced. This method is not useful in patients with HIV infection and immunodepression (AIDS). We have not observed any relationship between the serology and the response to PPD intradermorreaction. We conclude that this method could be used in our environment as a supplementary test, but in any case as a substitute of the traditional microbiological diagnosis.