FeedbackIt is estimated that about a quarter of the world’s population is infected with Mycobacterium tuberculosis (Mtb) – the bacterium that causes tuberculosis (TB) disease. Testing for TB infection can identify individuals who would benefit the most from TB preventive treatment (TPT). Without TPT, it is estimated that about 5–10% of people who are infected will develop TB disease over the course of their lives, usually within 5 years of the initial infection (1).
Despite the availability of preventive measures and disease treatment, TB remains a leading cause of death due to a single infectious agent, and has probably replaced coronavirus disease (COVID-19) as the leading cause of death worldwide for the first time since the start of the global pandemic (1). In 2023, it is estimated that 10.8 million people fell ill with TB, but only 8.2 million were diagnosed. In addition, resistance to the antibiotics that are used to treat TB remains a challenge, with an estimated 400 000 people (95% uncertainty interval [UI]: 370 000–450 000) having developed either rifampicin-resistant TB (RR-TB), or TB resistant to both rifampicin and isoniazid, defined as multidrug-resistant TB (MDR-TB).
In 2018, the United Nations (UN) held the world’s first high-level meeting on TB. The political declaration from the meeting included commitments by Member States to achieve four new global targets (2). These commitments were subsequently renewed at the second UN highlevel meeting in 2023; they included provision of TPT to at least 45 million people between 2024 and 2027, and reaching 90% of the estimated number of people who develop TB with quality-assured diagnosis and treatment from 2023 to 2027 (3). In addition, the World Health Organization’s (WHO’s) End TB Strategy calls for the detection of individuals living with TB infection who are at higher risk of progression to active TB so that they can receive TPT, as well as the early diagnosis of TB and universal drug susceptibility testing (DST). These global commitments and plans highlight the critical role of TB testing for the rapid and accurate detection of TB infection, disease and drug resistance (4).
Over recent years, the WHO Global TB Programme (WHO/GTB) has issued evidence-based policy guidance on diagnostic testing, to support countries in their efforts to detect TB infection, disease and drug resistance. When novel diagnostic tools are developed and evidence on their use and impact becomes available, WHO/GTB commissions systematic reviews and convenes guideline development groups (GDGs) to inform guideline updates. Since 2021, these updates have been issued in module-based consolidated guidelines. Until 2024, policy recommendations for testing for TB infection, TB disease and drug resistance were presented separately (in the consolidated guidelines on prevention and diagnosis, respectively).
This document is the fourth edition of WHO policy guidelines on TB diagnosis. Compared with the third edition, issued in 2024, this document:
- is the first to combine guidance on diagnosis of TB infection, disease and drug resistance into a single reference document;
- establishes two new classes of TB diagnostic technologies (for the initial detection of TB and resistance to rifampicin), which include tests previously recommended for use as individual products; and
- outlines new recommendations on concurrent testing of respiratory and non-respiratory samples among adults and adolescents with HIV, children with HIV, and children without HIV or with unknown HIV status.