S41 The diagnostic work up of pleural tuberculosis and the utility of GeneXpert: 5 year experience from a tertiary centre

• Published in: Thorax Vol. 76; no. Suppl 2; pp. A30 - A31
• Main Authors: Aung, H, Balasundaram, K, Goss, J, Patel, H, Haldar, P, Panchal, RK
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group Ltd and British Thoracic Society 08.11.2021; BMJ Publishing Group LTD
• Subjects: Beyond acid-fast: diagnosis and treatment of TB in the 21st Century; Biopsy; Cellular biology; Tuberculosis
• ISSN: 0040-6376; 1468-3296
• DOI: 10.1136/thorax-2021-BTSabstracts.47

BackgroundThe paucibacillary nature of Mycobacterium tuberculosis (MTB) in pleural fluid poses challenges in the diagnosis of pleural TB. GeneXpert (GX) is a molecular test which detects the presence of MTB DNA and is validated in sputum specimens. However, its role in pleural TB is unclear. We sought to analyse how a diagnosis of pleural TB may be achieved that also incorporated use of GX in pleural specimens.MethodRetrospective analysis of pleural TB cases on our institutional TB registry between 2015–2019 was performed. Patients underwent either diagnostic thoracentesis (DT), DT and local anaesthetic thoracoscopy (LAT) or direct to LAT. Pleural fluid and biopsy specimens were sent for culture/cytology and culture/histology, respectively. In a proportion of cases GX was performed [Xpert MTB/RIF pre-2018 and Xpert MTB/RIF Ultra 2018 onwards].ResultsAmong the 54 pleural TB cases, mean age was 46 years with 68% male. Unilateral disease was detected in 96%. 15/54 underwent DT only, 28 underwent DT+LAT and 11 underwent LAT only. Pleural fluid cytology was lymphocytic in 43%. Pleural fluid culture yielded a diagnosis in (7/43) 16% which was low in comparison to LAT pleural biopsy culture yield 21/39 (54%). LAT pleural biopsy yielded a histological TB diagnosis in 37/39 (95%). Pleural fluid GX MTB/RIF Ultra where performed was more sensitive than GX MTB/RIF in both pleural fluid (64% vs 0%) and pleural biopsy (33% vs 25%).Abstract S41 Figure 1Summary of outcomes from pleural sample analysisConclusionLAT plays an important role in the diagnosis of pleural TB. However, pleural fluid Xpert MTB/RIF Ultra demonstrates potential for added diagnostic value. Further studies are required.