Nucleic acid tests for detection of drug resistance in Mycobacterium tuberculosis complex: protocol for performance evaluation of in vitro diagnostics for WHO prequalification assessment

This protocol provides the methodology for the independent performance evaluation of nucleic acid tests (NATs) intended for the detection of drug resistance in the Mycobacterium tuberculosis complex as part of the World Health Organization prequalification assessment of in vitro diagnostics. Developed within the WHO prequalification framework, the document establishes standardized procedures for assessing commercially available molecular assays used on tuberculosis-positive specimens, concentrated sediments or culture isolates. The protocol is intended for performance evaluation laboratories and manufacturers and aims to verify a subset of manufacturer performance claims under controlled laboratory conditions.

The publication describes requirements for evaluating clinical and analytical performance, including sensitivity and specificity for drug resistance detection, limit of detection, reproducibility, inclusivity and exclusivity, resistance mutation detection, and assessment of cross-contamination or carry-over. It also outlines procedures for specimen selection, laboratory testing, quality control, data analysis, operational characteristics and ease of use, with particular attention to suitability for resource-limited settings. In addition, the protocol addresses ethical considerations, data management, reporting procedures and the respective responsibilities of evaluation laboratories, manufacturers and WHO. The document is intended to support transparent, consistent and rigorous assessment of tuberculosis molecular diagnostics submitted for WHO prequalification.