All parts of the WHO Mycobacterium tuberculosis mutation catalog need to be applied when evaluating its performance.

A limitation of the World Health Organization (WHO) mutation catalog, a global reference for genotypic antimicrobial susceptibility testing for Mycobacterium tuberculosis complex, is that it was derived and tested using the same data set, which may result in overfitting (1–4). Therefore, we welcome the effort by He et al. to assess the performance of both version 1 (V1) and version 2 (V2) catalog using an independent data set from China (5). However, we have concerns about how this was carried out.