Diagnosis of intestinal tuberculosis: a systematic review and meta-analysis

Background/Aims: Diagnosis of intestinal tuberculosis (ITB) is challenging. Histopathology and microbiological examination remain the gold standard, but previous studies show varied diagnostic performance. We aimed to systematically evaluate the accuracy of tests to diagnose ITB in both conventional and novel methods. Methods: We searched MEDLINE and EMBASE from inception to October 2023. All studies enrolling at least 10 patients with reported information regarding the diagnosis of ITB based on endoscopic biopsy specimens, stool tests, and blood tests were included. We performed a meta-analysis using a random-effects model to estimate the performance of each test. Results: Of 3,308 abstracts reviewed, 55 studies with 6,072 participants met the inclusion criteria. Endoscopic tissue biopsy for acid-fast bacilli, the presence of caseous granuloma on histopathology, polymerase chain reaction (PCR) for tuberculosis, mycobacterial culture, and Xpert MTB/RIF showed pooled sensitivity of 12% (95% confidence interval [CI], 8%-17%), 18% (95% CI, 12%-27%), 58% (95% CI, 44%-72%), 23% (95% CI, 12%-40%) and 29% (95% CI, 17%-46%), respectively. The liquid medium culture showed higher sensitivity than conventional Lowenstein-Jensen medium (25% [95% CI, 13%-43%] and 6% [95% CI, 3%-13%]). Pooled sensitivity and specificity of stool PCR for TB were 73% (95% CI, 43%-90%) and 95% (95% CI, 79%-99%), respectively. Additionally, the pooled sensitivity and specificity of interferon-gamma release assay (IGRA) were 86% (95% CI, 79%-91%) and 86% (95% CI, 81%-89%). Conclusions: Endoscopic tissue biopsy samples had limited sensitivity in diagnosing ITB. IGRA showed good accuracy and may be combined with other methods to improve the diagnostic yield. Stool PCR demonstrated a good performance but based on a few studies.