Evaluation of Gene Xpert Ultra Against Conventional Technique for the Diagnosis of Extrapulmonary Tuberculosis in Children in A Tertiary Care Center

Background: EPTB receives less attention than PTB because of its low infection potential. Clinically EPTB is still under recognized and diagnosis are often delayed due to its paucibacillary nature and atypical presentation. Proper diagnosis needs isolation of organism, that is always not possible by doing AFB staining, culture of different body fluid, biopsy only. Gene Xpert MTB/RIF Ultra (Xpert Ultra) was evolved to prevail over this limitation. Materials & Methods: In this prospective, single center, cross-sectional, diagnostic performance study which was conducted at the department of Paediatrics in Dhaka Medical College Hospital (DMCH), Dhaka, Bangladesh over 1 year period. Different body fluid (CSF, ascetic fluid, pleural fluid, pus etc) for AFB staining, micobacterialculture, Xpert MTB/RIF Ultra, biopsy for histopathology of children presenting with presumptive extra pulmonary tuberculosis were tested with Adenosine deaminase (ADA) & other baseline investigations. Total 80 children having the clinical features of extra pulmonary tuberculosis were enrolled and evaluated. Diagnostic performance (sensitivity, specificity, positive & negative predictive value) of Gene Xpert MTB/RIF Ultra were analyzed. Results: From January, 2021 to december, 2021 total 80 patients were evaluated. Among them, 17.5% were diagnosed as TBM & 11.3% were TB lymphadenitis, 6.3% were abdominal TB, 3.8% were pleural TB, 1.25% were spinal TB. AFB staining positive in 4.8% (3 of 62), culture growth positive in 8.06% (5 of 62) & Gene Xpert Ultra positive in 37.97% (30 of 79) cases. Against the mycobacterial culture results and AFB staining, Xpert Ultra had sensitivity of 100.0% (69.2 – 100.0; p 0.001) &100.0% (26.2 to 87.8; p 0.01), respectively. Xpert Ultra had specificity of 73.7% and 71.2% respectively. Conclusion: Xpert Ultra detected extra pulmonary tuberculosis with higher sensitivity than culture and AFB staining in paediatric population.