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Canadian Journal of Infectious Diseases and Medical Microbiology
Volume 23, Issue 3, Pages 114-116
http://dx.doi.org/10.1155/2012/287181
Original Article

Interferon-Gamma Release Assays Are a Better Tuberculosis Screening Test for Hemodialysis Patients: A Study and Review of the Literature

J Grant,1 J Jastrzebski,2 J Johnston,3 A Stefanovic,1 J Jastrabesky,2 K Elwood,3 D Roscoe,1 R Balshaw,1 and E Bryce1

1Division of Medical Microbiology, Department of Pathology and Laboratory Medicine, Vancouver General Hospital, Canada
2Division of Nephrology, Department of Internal Medicine, Vancouver General Hospital, Canada
3Tuberculosis Control, British Columbia Centres for Disease Control, Vancouver, British Columbia, Canada

Copyright © 2012 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Diagnosing latent tuberculosis (TB) infection (LTBI) in dialysis patients is complicated by poor response to tuberculin skin testing (TST), but the role of interferon-gamma release assays (IGRAs) in the dialysis population remains uncertain. Seventy-nine patients were recruited to compare conventional diagnosis (CD) with the results of two IGRA tests in a dialysis unit. Combining TST, chest x-ray and screening questionnaire results (ie, CD) identified 24 patients as possible LTBI. IGRA testing identified 22 (QuantiFERON Gold IT, Cellestis, USA) and 23 (T-spot.TB, Oxford Immunotec, United Kingdom) LTBI patients. IGRA and CD correlated moderately (κ=0.59). IGRA results correlated with history of TB, TB contact and birth in an endemic country. TST was not helpful in identifying LTBI patients in this population. The tendency for IGRAs to correlate with risk factors for TB, active TB infection and history of TB argues for their superiority over TST in dialysis patients. There was no superiority of one IGRA test over another.