The political declaration of the first United Nations (UN) high-level meeting on tuberculosis (TB) calls countries to diagnose and treat 40 million people with TB globally between 2018 and 2022. Traditionally, in most countries, TB diagnosis has been performed using sputum-smear microscopy, a method developed more than 100 years ago, with suboptimal sensitivity. In recent years new technologies have emerged based on the detection of mycobacterial DNA or mycobacterial antigens.
Over the past decade the World Health Organization (WHO) has published a number of guidelines developed by WHO-convened Guideline Development Groups (GDGs), using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach to summarize the evidence and to formulate policy recommendations and accompanying remarks. The present document “WHO consolidated guidelines on tuberculosis. Module 3: Diagnosis - Rapid diagnostics for tuberculosis detection” consolidates five guidelines developed by WHO between 2016 and 2020. Earlier guidelines on diagnostics that were not developed according to the GRADE approach have not been included in this document. The WHO Consolidated Guidelines on Tuberculosis will group all TB recommendations in one document and will be complemented by matching modules of an operational handbook. The handbook will provide practical advice on how to put in place the recommendations at the scale needed to achieve national and global impact.
A range of new diagnostic technologies have been endorsed by WHO during the past decade. These are listed below:
- real-time polymerase chain reaction (PCR) assays – for example, Xpert MTB/RIF® (Ultra) (cartridge-based) and Truenat™ (chip-based);
- line probe assays (LPAs) – for example, GenoType® MTBDRplus v1 and v2, Genoscholar™ NTM+MDRTB II and GenoType® MTBDRsl;
- loop-mediated isothermal amplification (LAMP) – for example, TB-LAMP; and
- antigen detection in a lateral flow format (biomarker-based detection) – for example, Alere Determine™ TB LAM Ag.
The present “WHO consolidated guidelines on tuberculosis. Module 3: Diagnosis - Rapid diagnostics for tuberculosis detection” provides background, justification and recommendations on these technologies. The document includes new recommendations on molecular assays intended as initial tests for the diagnosis of pulmonary and extrapulmonary TB and rifampicin resistance in adults and children.