title: Xpert® MTB/RIF for national tuberculosis programmes in low-income countries: when, where and how?
abstract: Xpert ® MTB/RIF offers new and important possibilities for the diagnosis of sputum smear-negative tuberculosis (TB) and/or rifampicin (RMP) resistance, and many are encouraging rapid and widespread implementation. This simple test can be implemented almost everywhere, and it provides results within a few hours. In low-income countries (LICs), however, its cost, environmental limitations (stable and regular electricity, adequate room temperature) and difficulties involved in supply and maintenance are major obstacles. While it may be suitable for major reference hospitals, operational research is needed to evaluate the test and its additional yield above high-quality smear microscopy and clinical algorithms before its use at the peripheral level. In the meantime, direct microscopy should remain the initial diagnostic test for TB suspects. In most LICs, the prevalence of RMP resistance among new TB patients is very low; an Xpert MTB/RIF result indicating RMP resistance will thus always need confirmation by another test. In a population at high risk of RMP resistance (> 15%), however, the positive predictive value for RMP resistance by Xpert MTB/RIF is high, and identification of RMP resistance is an excellent proxy for multidrug-resistant TB (MDR-TB). The assay should be widely used for this purpose if, and only if, excellent MDR-TB management is available, both for ethical reasons and to reduce the risk of extensively drug-resistant TB.
authors: Institute of International Union Against Tuberculosis and Lung Disease, Paris, France. atrebucq@theunion.org
authors: A
authors: A
authors: Trébucq
authors: D A
authors: DA
authors: Enarson
authors: C Y
authors: CY
authors: Chiang
authors: A
authors: A
authors: Van Deun
authors: A D
authors: AD
authors: Harries
authors: F
authors: F
authors: Boillot
authors: A
authors: A
authors: Detjen
authors: P I
authors: PI
authors: Fujiwara
authors: S M
authors: SM
authors: Graham
authors: I
authors: I
authors: Monedero
authors: I D
authors: ID
authors: Rusen
authors: H L
authors: HL
authors: Rieder
mesh_terms: D000465:Algorithms; D000995:Antitubercular Agents / Q000494:pharmacology*; D003906:Developing Countries; D024881:Drug Resistance, Bacterial; D006801:Humans; D008826:Microbial Sensitivity Tests; D009169:Mycobacterium tuberculosis / Q000187:drug effects; D009313:National Health Programs; D021141:Nucleic Acid Amplification Techniques / Q000191:economics / Q000379:methods*; D012293:Rifampin / Q000494:pharmacology*; D013183:Sputum / Q000382:microbiology; D014376:Tuberculosis / Q000175:diagnosis* / Q000188:drug therapy / Q000382:microbiology
chemical_list: D000995:Antitubercular Agents; D012293:Rifampin