Screening for tuberculosis and the use of a borderline zone for the interpretation of the interferon-γ release assay (IGRA) in Portuguese healthcare workers

  • Nienhaus A
  • Costa J
N/ACitations
Citations of this article
27Readers
Mendeley users who have this article in their library.

This article is free to access.

Abstract

UNLABELLED: INTRODUCTION: The effect of using a borderline zone for the interpretation of the interferon-γ release assay (IGRA) on the prediction of progression to active tuberculosis (TB) in healthcare workers (HCW) is analysed.METHODS: Data from a published study on TB screening in Portuguese HCW is reanalysed using a borderline zone for the interpretation of the IGRA. Testing was performed with the QuantiFERON-TB Gold In-Tube (QFT). The borderline zone for the QFT was defined as interferon (INF) in QFT ≥0.2 to <0.7 IU/mL. An X-ray was performed when the IGRA was positive (≥0.35 IU/mL) or typical symptoms were present. Sputum analysis was performed according to the X-ray or the presence of typical symptoms.RESULTS: The cohort comprised 2,884 HCW with a QFT that could be interpreted. In 1,780 (61.7%) HCW, the QFT was <0.2 IU/mL. A borderline result was found in 341 (11.8%) and a QFT >0.7 IU/mL in 763 (26.3%) HCW. Fifty-seven HCW had a TB in their medical history, eight had a TB at the time of screening and progression to active TB was observed in four HCW. Two out of eight HCW (25%) with active TB at the time of screening had a QFT result falling into the borderline zone. One out of four HCW (25%) who progressed towards active TB after being tested with QFT had QFT results falling into the borderline zone. A second IGRA was performed in 1,199 HCW. In total, 292 (24.4%) HCW had at least one of the two IGRA results pertaining to the borderline zone.CONCLUSION: Using a borderline zone for the QFT from 0.2 to 0.7 IU/mL should be administered with care, as active TB as well as progression to active TB might be overlooked. Therefore, the borderline zone should be restricted to populations with a low TB risk only.

Cite

CITATION STYLE

APA

Nienhaus, A., & Costa, J. T. (2013). Screening for tuberculosis and the use of a borderline zone for the interpretation of the interferon-γ release assay (IGRA) in Portuguese healthcare workers. Journal of Occupational Medicine and Toxicology, 8(1), 1. https://doi.org/10.1186/1745-6673-8-1

Register to see more suggestions

Mendeley helps you to discover research relevant for your work.

Already have an account?

Save time finding and organizing research with Mendeley

Sign up for free