What services are there to diagnose TB?
Situation in 2014
Laboratory confirmation of TB and drug resistance is essential to ensure that individuals with TB are correctly diagnosed and have access to the appropriate treatment as soon as possible.
Of the 5.2 million incident (new and relapse) pulmonary TB patients notified globally in 2014, 3.0 million (58%) were bacteriologically confirmed, i.e., were smear- or culture-positive or positive according to a WHO-recommended rapid diagnostic such as Xpert® MTB/RIF. Among new (previously untreated) cases of bacteriologically confirmed TB, 12% had access to drug susceptibility testing (DST); among previously treated cases, 58% had access to DST.
Smear microscopy continues to be the most widely used tool for TB diagnosis in low- and middle-income countries, despite its shortcomings. Globally, the target that countries maintain at least one smear microscopy centre per 100 000 population has been met (1.1 centres per 100 000 population in 2014), but significant disparities remain at regional and country levels.
The current target for both culture and DST (to at least rifampicin and isoniazid) capacity is one laboratory per 5 million population. In 2014, 12 of the 27 high MDR-TB burden countries did not reach the target, and several countries with large TB caseloads continue to completely lack in-country capacity for phenotypic DST.