Performance evaluation results of Xpert MTB/RIF molecular biology testing of tuberculosis laboratories during 2018-2022

Abstract

Background: According to the “Global TB report 2021” released in 2022, the tuberculosis incidence rate in Mongolia is 428 per 100,000 population, which is 3.2-4.4 times higher than the average of the world and NGO countries. There is still a large gap between the estimated incidence of TB and the number of newly diagnosed cases. Early detection of TB cases, initiation of treatment, and prevention of human-to-human transmission are important for full detection of estimated cases, and the more sensitive Xpert MTB/RIF test recommended by WHO has been used since 2013. This study is being conducted to evaluate the performance of Xpert MTB/RIF molecular biology tests performed in the tuberculosis diagnostic laboratories of our country, compare them with the international level, increase the benefits of the test, and determine the activities to be implemented in the future. Aim: To evaluate the performance of Xpert MTB/RIF molecular biological tests performed in tuberculosis diagnostic laboratories, to compare them with international standards, to increase the effectiveness of the test, and to determine the activities to be implemented in the future. Materials and Methods: We conducted this study using a retrospective research design. In this study, data on the performance of Xpert MTB/RIF tests conducted in the laboratory between 2018 and 2022 were collected and analyzed quantitatively using the nationally used electronic register (Tubis.mn) and the monthly reports of the Tuberculosis Reference Laboratory. Quantification of the results was done using percentage and SPSS-17 software. Ethical approval for the study was obtained from the Research Ethics Review Committee of ASSU. (#2023/3-02). Results: Between 2018 and 2022, a total of 139,876 M.tuberculosis tests were performed nationwide, of which 53% (74,179) were included in the Xpert MTB/RIF test, and M. tuberculosis was detected in 12,270 (16.6%) cases. M.tuberculosis was detected in 15.6% (95% CI: 15.4-15.9) of lung specimens, and 23.6% (95% CI: 22.7-24.5) of extrapulmonary specimens. 7.9% of M. tuberculosis was resistant to rifampicin, 89.9% was sensitive to rifampicin, and 2.2% could not be identified. Considering the total number of new TB cases by gender and age group, the incidence among men in all age groups is relatively high at 60.5% (7426/12270). According to the positive degree of M.tuberculosis detected by Xpert MTB/RIF test, 20% (2466) are high, 26% (3202) are medium, 35.7% (4381) are low, 16.7% (2048) are very low, 1.4 % (173) have positive trace indicators. Conclusion: The Xpert MTB/RIF coverage of half of the diagnostic cases is not sufÏcient and further coverage of the test is needed. According to the statistics of the last 5 years, the proportion of cases and rifampicin resistance diagnosed by molecular biology Xpert MTB/RIF test is increasing every year.