Purified antibodies that bind to M. tuberculosis ERP protein are disclosed. In one embodiment, a purified antibody, which binds specifically with a polypeptide comprising SEQ ID NO: 39 or SEQ ID NO: 41 is provided. In some embodiments the polypeptide has a theoretical molecular weight of about 28 kDa. In other embodiments the polypeptide has an observed molecular weight of about 36 kDa, as determined by denaturing polyacrylamide gel electrophoresis (SDS-PAGE). The purified antibody may be a monoclonal or a polyclonal antibody. Further embodiments provide antibodies that does not bind specifically with M. leprae P28 protein. The antibodies of the invention have many uses including the identification of M. tuberculosis.