The objective: to compare results of drug susceptibility testing to rifampicin by molecular genetic methods and phenotypic tests of Mycobacterium tuberculosis isolates obtained from clinical specimens of tuberculosis patients.Subjects and Methods. 915 samples of M. tuberculosis DNA and 426 cultures were used in this study. Genotypic tests (TB-TEST (BIOCIP-IMB, Russia), GenoType MTBDRplusV2) and phenotypic technologies (absolute concentration method, Bactec MGIT 960 system, Sensititre Myco TB

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... ) were used.Results. A high percentage (98.7%; CI 97.7-99.7%) of confirmation of the results of the molecular genetic test (TB-TEST) by the phenotypic test (absolute concentration method) was demonstrated. In some cases, the Bactec MGIT 960 system as well as the absolute concentration method were shown to produce false negative results of rifampicin resistance in some cases.