Organization practice and efficiency of laboratory diagnosis of tuberculosis with an automatic GeneXpert PCR analyzer in the Belgorod Region

Objective. To develop: an optimal model and to estimate its efficiency for the laboratory diagnosis of tuberculosis, by applying an automatic GeneXpert PCR analyzer. Materials and methods. The investigators studied the efficiency of detecting the pathogen of tuberculosis, by using an automatic GeneExpert PCR analyzer versus routine bacteriological methods, and analyzed the coverage rates through patient examination and the proportion of tuberculosis cases diagnosed with the GeneXpert. Results. The effective organizational model for the detection of tuberculosis, including multidrug resistant tuberculosis, by using the automatic GeneXpert analyzer, was implemented in the Belgorod Region. The coverage rate for new and recurrent pulmonary tuberculosis cases exceeded 70%. More than half of all tuberculosis cases with bacterial excretion were detected using the GeneXpert. The time taken to detect the pathogen of tuberculosis with the GeneXpert averaged 2.3 days. The efficiency of detecting the pathogen of tuberculosis was slightly lower than that of a culture method and accounted for 50.4 and 72.7% for new and recurrent pulmonary tuberculosis cases, respectively. The sensitivity and specificity of the GeneXpert versus routine bacteriological methods in determining the pathogen’s resistance to rifampin in the sputum of new pulmonary tuberculosis cases were as high as 90-95%. Conclusion. The introduction of the procedure for detecting the pathogen of tuberculosis and determining its resistance to rifampicin with the automatic GeneXpert PCR analyzer into the practice of the phthisiatric service of the Belgorod Region and the elaboration of the optimal model for using the device could ensure a high specificity in the etiological diagnosis of most epidemically dangerous new and recurrent pulmonary tuberculosis cases in the region for a short period beyond 4 days.

automatic PCR analyzer GeneXpert, Mycobacterium tuberculosis, drug resistance, sensitivity and specificity of the method