DIAGNOSTIC VALUE OF GENEXPERT MTB/RIF ASSAY FOR TUBERCULOSIS DIAGNOSIS COMPARED TO TRADITIONAL METHODS

GeneXpert MTB/Rif assay for rapid diagnosis of tuberculosis and detection of rifampicin resistance can reduce the time to diagnosis and initiation of treatment. Aim. To evaluate the sensitivity and specificity of the GeneXpert MTB/Rif assay compared with traditional methods of detecting Mycobacterium tuberculosis (smear microscopy, culture on liquid and solid media). Material and methods. The results of sputum tests for detection of Mycobacterium tuberculosis (MBT) by bacteriological and molecular genetic methods in 1355 patients diagnosed with tuberculosis during 2016-2020 years were analyzed. Results. The informative value of the GeneXpert MTB/Rif assay was no different to the culture method (for infiltrative TB - 78.4% vs. 80.9%, p=0.138; for disseminated TB, 75.0% versus 79.0%, p=0.384) and higher compared to smear microscopy (for infiltrative TB, 78.4% versus 49.8%, р<0.001; for disseminated TB, 75.0% versus 61.9%, p=009). At high accuracy (85.0%), the sensitivity of the GeneXpert MTB/Rif assay versus the culture on liquid and solid media was 89.1% and specificity – 67.9%. The GeneXpert MTB/Rif method allows for early diagnosis of TB when the clinical and radiological signs are not clear. However, due to low specificity the results of the method should be further confirmed by the classical microbiological methods of diagnostics. Conclusions. The results of this study confirm the high diagnostic value of using GeneXpert MTB/Rif in phthisiology practice, especially for newly diagnosed patients.