To support countries and technical agencies in their efforts to strengthen detection of tuberculosis (TB), the World Health Organization (WHO) published the WHO consolidated guidelines on tuberculosis. Module 3: Diagnosis today. When compared with the previous edition issued in 2024, this guideline is the first to:
- Combine the WHO policy guidance on diagnosis of TB infection, disease and drug resistance into a single reference document
- Present new recommendations on concurrent testing of respiratory and non-respiratory samples among people of all ages living with HIV and children without HIV or with unknown HIV status
- Establish two new classes of TB diagnostic technologies for the initial detection of TB and resistance to rifampicin, and
- Outline current WHO TB diagnostic class determination and product assessment definitions and pathways.
The WHO operational handbook on tuberculosis. Module 3: Diagnosis will accompany these WHO consolidated guidelines. The WHO operational handbook provides laboratory personnel, clinicians and other clinical staff, as well as ministries of health and technical partners, detailed guidance on implementing the WHO evidence-based recommendations. Updates in the companion Handbook include consolidation of guidance on TB infection, diagnosis, and drug resistance testing, considerations for the implementation of new diagnostic classes and concurrent testing strategies, and presentation of policy statements on the use of new or updated interferon gamma release assays for the detection of TB infection, as well as targeted next generation sequencing solutions for the detection of drug-resistant TB. These class and product advances are followed by an overview of the steps and processes required to implement and scale up new tests for TB detection and revised model diagnostic algorithms that reflect the new WHO TB testing policy recommendations.
Main changes to the guidance in this update
- Two new classes of TB diagnostic tests for the initial detection of TB and resistance to rifampicin were established; these classes differ in the level of procedure and test result automation, and include tests that were previously recommended as standalone products. The new low-complexity automated nucleic acid amplification test (LC-aNAAT) class includes the Xpert® MTB/RIF and Xpert MTB/ RIF Ultra assays, and the Truenat® MTB Plus and MTB-RIF Dx assays. The lowcomplexity manual nucleic acid amplification test (LC-mNAAT) class includes the LoopampTM MTBC Detection Kit (TB LAMP) (Eiken Chemical). These new classbased recommendations supersede previous product-specific recommendations.
- Concurrent testing of respiratory and non-respiratory samples for the initial detection of TB and resistance to rifampicin is newly recommended for adults and adolescents living with HIV, children living with HIV, and children without HIV or with unknown HIV status.Existing guidelines on tests for TB infection were added, to consolidate policy guidance on testing for TB diagnosis, drug resistance and infection.
- A description of TB diagnostic test determination and the pathways for TB diagnostic product prequalification by WHO was added to the Background section.
- TB diagnostic test class description tables were revised to align with the classdetermination criteria presented in the Background section.
- The four prior web annexes covering systematic review and guideline development group (GDG) evidence to inform policy updates were consolidated into two web annexes. Web Annex A includes the systematic reviews, Grading of Recommendations Assessment, Development and Evaluation (GRADE) tables and evidence to decision (EtD) tables, and Web Annex B includes the evidence synthesis and analysis findings. Both web annexes now present content by TB diagnostic class
