This guide was developed to provide practical guidance for the implementation of WHO policies on recommended TB diagnostic tests and algorithms. The guide:
- describes the WHO-recommended tests for detecting TB and DR-TB and the most recent WHO policy guidance for their use, and the processes and steps needed for implementing a diagnostic test for routine use within the TB diagnostic network (Section 2) – important additions in this update are the recommendations for the use of targeted NGS as a follow-on test for detection of drug resistance, newly defined critical concentrations (CCs) for phenotypic DST of Pa and CS, and the updated technical manual for culture-based phenotypic DST;
- describes the steps that need to be taken to implement a new diagnostic tool (Section 3); and
- outlines TB diagnostic model algorithms that incorporate the most recent WHO recommendations for detecting and treating TB and DR-TB (9), and considerations for the implementation of a new algorithm (Section 4).
The 3rd edition is an update of the previous operational handbook (11) with relevant chapters updated. A significant change that necessitated the update is the new recommendations on the use of targeted next generation sequencing for the detection of drug resistance (7) and this handbook includes operational considerations for implementation. WHO has developed an online e-learning course that complements the content of the operational handbook. The self-paced course covers all the major topics in this handbook and includes videos covering the different tests (12).
This guide is not intended to be a comprehensive manual, nor does it repeat information provided by other guidance documents such as those listed in Annex 4; rather, the guide provides references and links to original resources.
The most up-to-date WHO policy guidance on TB diagnostics and laboratory strengthening can be found in the most recent edition of the consolidated guidelines on this topic (13). Guidance on the implementation of diagnostic testing is also available on the website of the Global Laboratory Initiative (GLI) of the Stop TB Partnership (14).