Diagnosis

As highlighted above, all technologies with a WHO/GTB recommendation are expected to undergo prequalification assessment, as available. Successful assessment will be required to maintain a WHO/GTB recommendation. The current set of TB diagnostic testing classes and included products are listed in Table 1.1.1, and the two new classes are discussed below.

Over the past 16 years, WHO has endorsed a range of diagnostic technologies (Table 1.1.1). The WHO assessment process for TB diagnostics has recently evolved to focus on evaluating classes of TB diagnostic technologies rather than specific products. Class determination is managed by WHO/GTB for new diagnostic testing technologies, and it includes an evaluation of the following characteristics:

It 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).

It is estimated that about a quarter of the world’s population is infected with Mycobacterium tuberculosis – the bacterium that causes tuberculosis (TB) disease. Testing for TB infection can identify individuals who would benefit the most from TB preventive treatment (TPT). However, despite the availability of preventive measures and disease treatment, TB remains a leading cause of death due to a single infectious agent.

Advanced HIV disease: for adults, adolescents, and children aged 5 years or more, “advanced HIV disease” is defined as a CD4 cell count of less than 200 cells/mm³ or a WHO clinical stage 3 or 4 event at presentation for care. All children living with HIV aged under 5 years should be considered as having advanced disease at presentation.

Age groups: the following definitions for adults and children are used in these guidelines for the purpose of implementing recommendations (countries may have other definitions under their national regulations):

The recommendations and remarks in this policy guideline on tuberculosis (TB) are the result of the collaborative effort of professionals from a range of specialties. The World Health Organization (WHO) is grateful for their time and support. There were separate Guideline Development Groups (GDGs) for each of the guidelines that have been included in these consolidated guidelines. The acknowledgements provided immediately below are specific to WHO guidelines that are new in this edition. Acknowledgements for prior guidelines are summarized in Web Annex A.