Diagnostic delays and clinical decision making with centralized Xpert MTB/RIF testing in Durban, South Africa.

Setting: We conducted a retrospective study among HIV-infected adult suspects (≥18 years) with pulmonary tuberculosis (TB), who underwent Xpert MTB/RIF (Xpert) testing at McCord Hospital and its adjoining HIV clinic in Durban, South Africa. Objective: To determine if Xpert testing performed at a centralized laboratory accelerated time to TB diagnosis. Design: We obtained data on sputum smear microscopy [acid-fast bacilli (AFB)], Xpert, and the rationale for treatment initiation from medical records. The primary outcome was “total diagnostic time,” defined as time from sputum collection to clinicians' receipt of results. A linear mixed-effect model compared the duration of steps in the diagnostic pathway across testing modalities. Results: Among 403 participants, the median “total diagnostic time” for AFB and Xpert was 3.3 and 6.4 days, respectively (P Conclusions: In our setting, Xpert results took twice as long as AFB results to reach clinicians. Replacing AFB with centralized Xpert may delay TB diagnoses in some settings.