Difficulties in proper evaluation of tuberculous changes in x-ray imaging and imperfection of bacteriological examination are major problems of contemporary phthisiatry. In the beginning of the 1980s the new automatic system of Mycobacterium tuberculosis culture was introduced - BACTEC. It allowed to shorten the time of bacteriological diagnosis of the disease to 20 days. The polymerase chain reaction (PCR) which was developed in mid 1980s enables multiplication of Mycobacterium DNA sequence in vitro and obtaining the positive result after 2-3 days. The possibility of detecting the genetic material of 10 DNA fragments is an advantage in assessing the specimens of very low content of Mycobacterium tuberculosis. The PCR method also is useful in detecting Myc. tuberculosis presence in samples of tissues embedded in formalin or paraffin. The comparison of traditional methods and PCR technique shows the advantages of the latter. The accuracy and precision of PCR method is about 97-99%. The major disadvantage is the fact that we cannot distinguish between the active growth phase and resting phase of Myc. tuberculosis using PCR.

Keywords: Tuberculosis, diagnostics, PCR