# Proficiency of phenotypic drug susceptibility testing for Mycobacterium tuberculosis in China, 2008–2021

## TL;DR

This study evaluates the accuracy of drug susceptibility testing for tuberculosis in China from 2008 to 2021, showing improvements in some areas but persistent issues with specific drugs.

## Contribution

The study provides a comprehensive analysis of phenotypic DST proficiency in China over 13 years, identifying drugs where performance remains suboptimal.

## Key findings

- Specificity improved over time for all drugs, but sensitivity for amikacin and capreomycin did not.
- Accordance and reproducibility for pyrazinamide and kanamycin remained low despite testing improvements.
- Most labs improved DST quality, but issues persist with second-line injectables and pyrazinamide.

## Abstract

To analyze the results of proficiency testing for anti-tuberculosis drug susceptibility testing (DST) in China. Number of laboratory participating the proficiency testing performed DST, and the sensitivity, specificity, reproducibility, and accordance rate were calculated from data of 13 rounds proficiency testing results for DST from 2008 to 2021. A total of 30 and 20 strains of Mycobacterium tuberculosis with known susceptibility results were sent to each laboratory in 2008 to 2019, 2020 and 2021, respectively. The number of participating laboratories ranged from 30 in 2009 to 546 in 2021. L-J DST was the predominant method. The specificity presented relatively higher than sensitivity. Improvement of specificity were observed for all drugs through the years, while sensitivity did not show improvement for amikacin and capreomycin. Accordance rate of pyrazinamide and kanamycin and reproducibility of capreomycin and pyrazinamide were not significantly improved through the years. Most of the participating laboratories significantly improved the quality of their DST through the consecutive rounds of proficiency testing except for second-line injectable drugs and pyrazinamide. The results highlight the importance of developing novel and/or improving existing methods for phenotypic DST for certain drugs.