Recent Developments in the Laboratory Diagnosis of Tuberculosis

Despite breakthroughs in tuberculosis (TB) laboratory detection over the last 30 years, only a small part of the global population has benefited. The World Health Organization (WHO) recommends using nucleic acid amplification tests (NAAT) to detect tuberculosis rather than smear microscopy since NAAT can detect TB with greater precision, especially in patients with paucibacillary illness and HIV-positive persons. A variety of molecular TB detection assays are now being developed and reviewed, some for use in reference laboratories and others for peripheral medical care settings and point-of-care. There has been an increase in the number of molecular tests designed, manufactured, and implemented in countries with a high TB burden, and some are specifically intended for use in locations close to the patient. NAAT with next-generation sequencing may deliver faster findings than standard phenotypic culture in drug susceptibility testing. Furthermore, the results of tests that detect or quantify cytokines released during the inflammatory process in latent tuberculosis infection (LTBI), such as the Interferon-Gamma Release Assay (IGRA), or that quantify IL-6 or other cytokines, depend, as do tuberculin skin tests (TST), on the prevalence of TB in the tested population. We review recent advances in TB detection tests and anti-TB drug resistance in this paper.