Impact of the Xpert MTB/RIF diagnostic test for tuberculosis in countries with a high burden of disease.

PURPOSE OF REVIEW: Control of tuberculosis necessitates prompt diagnosis and access to effective treatment. We discuss the impact of a new nucleic acid amplification test to assist diagnosis and detect rifampicin resistance. Following encouraging clinical performance studies, an automated PCR-based test, the Xpert MTB/RIF (Cepheid, Sunnyvale, CA), has been implemented on a global scale. Clinical trials to assess the impact of the new technology in primary healthcare clinics have been undertaken in tuberculosis (TB) endemic countries. RECENT FINDINGS: Clinical trials at the point of care in TB endemic countries demonstrated that increased numbers of TB patients are identified using the Xpert MTB/RIF assay as the frontline diagnostic test in place of sputum smear microscopy. Decreased times from sample collection to initiation of treatment were also reported when using the molecular test. However, overall case notification rates did not improve, and no significant impact on patient outcome (morbidity or mortality) was reported. SUMMARY: Sensitive molecular tests to assist diagnosis of tuberculosis may provide a faster diagnostic result when used in clinics and laboratories, but the limited impact on patient outcomes suggests additional interventions are needed to enhance TB control.