Impact of the Xpert(®) MTB/RIF molecular test on the late diagnosis of pulmonary tuberculosis.

We analysed the impact of the Xpert(®) MTB/RIF molecular test on health-care diagnostic delay among tuberculosis patients. Diagnostic delay was 17.2 days (standard deviation 23.2, median 10 days). Of 128 patients recruited into the study, 60 (47%) were smear-negative; of these, 40 (67%) were Xpert-positive and were started on treatment without culture. The sensitivity of smear microscopy was 53% compared with 82% for Xpert. In smear-negative patients, delay in Xpert-positive and -negative patients was respectively 15.5 ± 13.2 and 25.5 ± 12.5 days (P = 0.002). We conclude that Xpert results were significantly associated with shorter health-care diagnostic delay, particularly in smear-negative patients.