Objective: To evaluate the performance of drug susceptibility testing (DST) against the main second-line (SL) anti-tuberculosis drugs in tuberculosis (TB) laboratories in China.
Method: The supranational TB reference laboratory issued 30 Mycobacterium tuberculosis isolates to the participating laboratories. Each participating laboratory performed DST against kanamycin (KM), amikacin (AMK), capreomycin (CPM) and ofloxacin (OFX) using the proportion method in Löwenstein-Jensen medium per World Health Organization recommendations. Reported results were checked and compared with the judicial results.
Result: The main performance indicators for the four anti-tuberculosis drugs evaluated (KM, AMK, CPM, OFX) were as follows: accordance rates: 91.62%, 99.16%, 96.93% and 96.37%; reproducibility: 99.16%, 99.16%, 94.96% and 94.12%; specificity: 99.12%, 99.64%, 98.00% and 98.41%; sensitivity: 78.03%, 97.62%, 94.44% and 91.51%. The accordance rates and sensitivity values of the four drugs showed statistically significant differences, while specificities showed no significant differences.
Conclusion: Eight (66.7%) participating laboratories met the set requirement criteria; however, DST in four (33.3%) laboratories requires greater attention. Of the four drugs tested, the results for KM were lower than those for the other drugs. External quality assessment can lead to effective evaluation of laboratory performance in SL DST.