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Inflamm Bowel Dis. 2014 Nov;20(11):2067-72. doi: 10.1097/MIB.0000000000000147.

Performance of interferon-gamma release assay for tuberculosis screening in inflammatory bowel disease patients.

Author information

1
*Institute of Digestive Disease, State Key Laboratory of Digestive Diseases, Department of Medicine and Therapeutics, and LKS Institute of Health Science, The Chinese University of Hong Kong, Hong Kong, China; †Department of Microbiology, The Chinese University of Hong Kong, Hong Kong, China; ‡Department of Imaging and Interventional Radiology, Prince of Wales Hospital, Hong Kong, China; and §Division of Infectious Disease, Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong, China.

Abstract

BACKGROUND:

Screening for latent tuberculosis (TB) is mandatory in inflammatory bowel disease (IBD) before starting anti-tumor necrosis factor therapy. Data on the utility of screening tests in populations with moderate background risk of TB are limited. This study aims to evaluate the performance of interferon-gamma release assay (IGRA) with QuantiFERON-TB Gold in IBD patients in a TB endemic region.

METHODS:

Two hundred sixty-eight consecutive adult IBD patients and 234 healthy controls were prospectively recruited. Detailed clinical history, chest x-ray findings, and IGRA results were documented for all individuals. The IGRA positive rates between IBD patients, with or without immunosuppressant, and healthy controls were compared.

RESULTS:

The IGRA result was positive in 21.9% of IBD patients and 19.2% of healthy controls (P = 0.535). IBD patients on immunosuppressive therapy had a significantly lower IGRA positive rate (13.0% versus 29.6%; P = 0.002) compared with immunosuppressant-naive IBD patients. This difference seemed to be most prominent for patients taking azathioprine (11.8% versus 27.3%, P = 0.006).

CONCLUSIONS:

IGRA results are negatively impacted by immunosuppressive therapy. Current guidelines suggesting TB screening before anti-tumor necrosis factor therapy may be inadequate in patients already on immunosuppressive drugs. Latent TB testing seems best performed before the initiation of immunosuppressive therapies in IBD patients.

PMID:
25159454
DOI:
10.1097/MIB.0000000000000147
[Indexed for MEDLINE]

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