Evaluation of the Xpert® MTB/RIF Assay and Microscopy for Diagnosing Pulmonary Tuberculosis in Butembo, Democratic Republic of the Congo

Objective: This study aimed to evaluate the efficacy of Xpert® MTB/RIF assay comparing to the acid-fast smear microscopy for diagnosing pulmonary tuberculosis cases in Butembo, Democratic Republic of the Congo.

Methodology: This was a retrospective study analyzing pulmonary tuberculosis cases that were diagnosed using both the Xpert® MTB/RIF assay and microscopy. Secondary data were collected from monthly report from the Microbiology department at GHR Katwa, Butembo, for the time period of February 2015 to September 2017.

Results: Three hundred and seventy-two specimens were collected from patients suspected of pulmonary tuberculosis. Of these, 98 (26.3%) were found to be positive for MTB by Xpert® MTB/RIF assay, out of which 73 (19.6%) were also found to be positive by microscopy. The remainder was negative. Two (2.04%) cases of resistance to rifampicin were detected. The sensitivity, specificity, positive predictive value and negative predictive value of Xpert assay were respectively 83.6%, 87.6%, 62.2% and 95.6%.

Conclusion: The use of the Xpert® MTB/RIF coupled with microscopy as part of routine assay, permits rapid diagnosis of pulmonary MTB and detection of rifampicin resistance. It may help in the epidemiological control of pulmonary MTB.