Concordance between tuberculin skin test and interferon-gamma release assay for latent tuberculosis screening in inflammatory bowel disease

Abstract

Background/Aims: Latent tuberculosis screening is mandatory prior to initiating anti-tumor necrosis factor (anti-TNF) medications. Guidelines recommend interferon-gamma release assays (IGRA) as first line screening method for the general population. Studies provided conflicting evidence on IGRA and tuberculin skin test (TST) performance in inflammatory bowel disease (IBD) patients. We assessed test concordance and the effects of immunosuppression on their performance in IBD patients.Methods: We searched MEDLINE, Embase and Cochrane databases (2011–2018) for studies testing TST and IGRA in IBD. Primary outcome was TST and IGRA concordance. Secondary outcomes were effects of immunosuppressive therapy on performance. Immunosuppression defined as either steroids, thiopurine, methotrexate or cyclosporine use. We used the pooled random effects model to adjust for heterogeneity analyzed using (I<sup>2</sup>–Q statistics). We compared the fixed model to exclude smaller study effects.Results: Sixteen studies (2,488 patients) were included. Pooled TST and IGRA concordance was 85% (95% confidence interval [CI], 81%–88%; <i>P</i>=0.01). Effects of immunosuppression were reported in 8 studies (814 patients). The odds ratio of testing positive by IGRA decreased to 0.57 if immunosuppressed (95% CI, 0.31–1.03; <i>P</i>=0.06). The odds ratio of testing positive by TST if immunosuppressed was 1.14 (95% CI, 0.61–2.12; <i>P</i>=0.69). The fixed model yielded similar results, however the negative effect of immunosuppression on IGRA reached statistical significance (<i>P</i>=0.01).Conclusions: While concordance was 85% between TST and IGRA, the performance of IGRA seems to be negatively affected by immunosuppression. Given the importance of detecting latent tuberculosis prior to anti-TNF initiation, further randomized controlled trials comparing the performance of TST and IGRA in IBD patients are needed.

Evaluation of Interferon Gamma Release Assay in the Diagnosis of Active and ‎Latent Tuberculosis among Patients and Contacts ‎

“…IGRA is recommended to be used in immunocompromised as HIV-infected individuals as it is not affected by immunosuppression [23]. Furthermore, in this study, a positive HIV patient resulted in positive QFT-GIT that supported this finding.…”

Risk and characteristics of tuberculosis after anti-tumor necrosis factor therapy for inflammatory bowel disease: a hospital-based cohort study from Korea

“…Finally, the diagnostic tests for LTBI are not completely accurate. The TST and IGRA are more likely to produce false negative results if the patients are taking drugs such as steroids or immunomodulators, or if they have an immunodeficiency [ 37 – 39 ]. In addition, IGRA has a relatively low sensitivity compared with its high specificity; therefore, the possibility of false-negative results should be considered.…”

“…First, LTBI evaluation was conducted in accordance with the Korean guidelines, so we did not consider several factors that can affect the test results. In particular, BCG vaccination can affect TST results and is mandatory in Korea [ 40 ], and immunosuppressants and various diseases can also affect result of TST and IGRA [ 37 – 39 ]. Second, although the age at which anti-TNF therapy was initiated correlated with the incidence rate of TB, the time taken for TB to develop varies; therefore, care must be taken when interpreting this result.…”

Differentiating between Intestinal Tuberculosis and Crohn’s Disease May Be Complicated by Multidrug-resistant Mycobacterium tuberculosis

“…To overcome this limitation, diagnostic prediction models by colonoscopic findings were developed, or an interferon-gamma release assay test was used to make the differential diagnosis between ITB and CD [8][9][10][11]. However, this test can provide falsenegative results and its performance can be decreased by other medications such as immunosuppressants [12]. Despite these diagnostic efforts, in cases in which it is difficult to distinguish ITB from CD, it is considered appropriate to administer empirical anti-TB drugs and evaluate the clinical/endoscopic response in 2 to 3 months [13].…”