P202 Meta-analysis: accuracy of interferon-γ release assays in differentiating intestinal tuberculosis from Crohn’s disease in Asia
H. Xu*1, Y. Li2, J. Qian2
1Peking Union Medical College Hospital, Chinese Academy of Medical Science &Peking Union Medical College, Department of Gastroenterology, Beijing, China, 2Peking Union Medical College Hospital, Chinese Academy of Medical Science & Peking Union Medical College, Department of Gastroenterology, Beijing, China
Intestinal tuberculosis (ITB) and Crohn’s disease (CD) are similar in clinical, radiographic, endoscopic, and even histologic features,1 whereas they are widely divergent in treatments, which may lead to bad, even life-threatening prognosis. The distinction between these 2 diseases has become a clinical challenge, especially in tuberculosis-endemic countries. Our meta-analysis assessed the role of interferon-γ release assays (IGRAs) in distinguishing ITB from CD.
Systematic search without language restriction was conducted in the main computerised databases (PubMed, EMBase, Cochrane Library, Web of Science, CNKI, and Sinomed) until June 2015. Studies that have evaluated performance of IGRAs (QuantiFERON-TB Gold or T-SPOT.TB) in distinguishing ITB from CD were eligible. Main outcome measures included sensitivity and specificity. Area under the curve (AUC) of the summary receiver operating characteristic (sROC) curve was used to measure accuracy of IGRAs.2,3
Twelve studies involving 820 subjects were included, which are all from Asian countries where TB is endemic. The pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio of IGRAs for the diagnosis of ITB was 82.8% (95% CI 78.4–86.6), 86.7% (95% CI 83.2–89.6)
, 6.870 (95% CI 5.345–8.830), 0.171 (95% CI: 0.105–0.279), and 44.030 (95% CI: 27.964–69.325), respectively, with an AUC of 0.939.
Figure 1. Forest plot of sensitivity and specificity for interferon-gamma release assays in the differential diagnosis of intestinal tuberculosis from Crohn’s disease.
Figure 2. Summary receiver operating characteristic curves for interferon-gamma release assays.
IGRAs have a high sensitivity and specificity for the diagnosis of ITB, and specificity estimates for IGRAs were consistently high across studies. IGRAs may have a supplementary role in the differential diagnosis between ITB and CD. In countries with high prevalence of TB, IGRA may play a positive role for ruling out TB before using anti-TNF agents in patients with CD.
 Almadi MA, Ghosh S, Aljebreen AM. Differentiating intestinal tuberculosis from Crohn’s disease: a diagnostic challenge, Am J Gastroenterol 2009;104:1003–12.
 Deeks JJ. Systematic reviews in health care: systematic reviews of evaluations of diagnostic and screening tests. BMJ 2001; 323(7305):157–62.
 Deville WL, Buntinx F, Bouter LM, et al. Conducting systematic reviews of diagnostic studies: didactic guidelines. BMC Med Res Methodol 2002;2:9.