Examination of respiratory specimens improves microbiological diagnosis of patients with presumptive extrapulmonary tuberculosis.

Abstract Objectives Bacteriological confirmation of extrapulmonary tuberculosis (EPTB) is challenging for several reasons. Paucibacillary nature of the sample; scarce resources, mainly in middle and low-income countries; the need for hospitalization and, unfavorable outcomes. We evaluated prospectively the diagnostic role of respiratory specimen examination in a cohort of patients with presumptive EPTB. Methods From July 2018 to January 2019 in a TB/HIV reference hospital, a cohort of 157 patients with presumed EPTB was evaluated. Xpert® MTB/RIF Ultra or culture positive result was considered for bacteriologically confirmed tuberculosis (TB). Results Out of 157 patients with presumptive EPTB, 97 (62%) provided extrapulmonary and respiratory specimens, whereas 60 (38%) collected extrapulmonary specimens only. Of the 60 patients with extrapulmonary samples, 5 (8%) were positive. Of those with respiratory and extrapulmonary samples examined, 27 (28%) were positive: 10 in both respiratory and extrapulmonary samples, 6 in the extrapulmonary sample and 11 only in the respiratory sample. Having a respiratory specimen examined increased by 6-fold the chance of bacteriological confirmation of TB (odds ratio = 5.97 [1.11-47.17]). Conclusion We conclude that respiratory samples should be examined in patients with presumptive EPTB.