The Impact of Borderline Quantiferon-TB Gold Plus Results for Latent Tuberculosis Screening under Routine Conditions in a Low-Endemicity Setting
(2021) In Journal of Clinical Microbiology 59(12). p.0137021-0137021- Abstract
Quantiferon-TB Gold Plus (QFT-Plus) is an interferon gamma release assay used to diagnose latent tuberculosis (LTB). A borderline range (0.20 to 0.99 IU/ml) around the cutoff (0.35 IU/ml) has been suggested for the earlier QFT version. Our aims were to evaluate the borderline range for QFT-Plus and the contribution of the new TB2 antigen tube. QFT-Plus results were collected from clinical laboratories in Sweden and linked to incident active TB within 3 to 24 months using the national TB registry. Among QFT-Plus results from 58,539 patients, 83% were negative (<0.20 IU/ml), 2.4% were borderline negative (0.20 to 0.34 IU/ml), 3.4% were borderline positive (0.35 to 0.99 IU/ml), 9.6% were positive (≥1.0 IU/ml), and 1.6% were... (More)
Quantiferon-TB Gold Plus (QFT-Plus) is an interferon gamma release assay used to diagnose latent tuberculosis (LTB). A borderline range (0.20 to 0.99 IU/ml) around the cutoff (0.35 IU/ml) has been suggested for the earlier QFT version. Our aims were to evaluate the borderline range for QFT-Plus and the contribution of the new TB2 antigen tube. QFT-Plus results were collected from clinical laboratories in Sweden and linked to incident active TB within 3 to 24 months using the national TB registry. Among QFT-Plus results from 58,539 patients, 83% were negative (<0.20 IU/ml), 2.4% were borderline negative (0.20 to 0.34 IU/ml), 3.4% were borderline positive (0.35 to 0.99 IU/ml), 9.6% were positive (≥1.0 IU/ml), and 1.6% were indeterminate. Follow-up tests after initial borderline results were negative (<0.20 IU/ml) in 38.3%, without any cases of incident active TB within 2 years. Applying the 0.35-IU/ml cutoff, 1.5% of TB1 and TB2 results were discrepant, of which 52% were within the borderline range. A TB2 result of ≥0.35 IU/ml with a TB1 result of <0.20 IU/ml was found in 0.4% (231/58,539) of all included baseline QFT-Plus test results, including 1.8% (1/55) of incident TB cases. A borderline range for QFT-Plus is clinically useful as more than one-third of those with borderline results are convincingly negative upon retesting, without developing incident active TB. The TB2 tube contribution to LTB diagnosis appears limited.
(Less)
- author
- organization
- publishing date
- 2021-11-18
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- active tuberculosis, borderline-range results, interferon gamma release assay, latent tuberculosis, Quantiferon Plus
- in
- Journal of Clinical Microbiology
- volume
- 59
- issue
- 12
- pages
- 0137021 - 0137021
- publisher
- American Society for Microbiology
- external identifiers
-
- pmid:34550805
- scopus:85122048485
- ISSN
- 1098-660X
- DOI
- 10.1128/JCM.01370-21
- language
- English
- LU publication?
- yes
- id
- da9b78cd-0615-4538-82a7-da1df189e4f8
- date added to LUP
- 2022-02-21 10:56:33
- date last changed
- 2024-09-19 20:00:43
@article{da9b78cd-0615-4538-82a7-da1df189e4f8, abstract = {{<p>Quantiferon-TB Gold Plus (QFT-Plus) is an interferon gamma release assay used to diagnose latent tuberculosis (LTB). A borderline range (0.20 to 0.99 IU/ml) around the cutoff (0.35 IU/ml) has been suggested for the earlier QFT version. Our aims were to evaluate the borderline range for QFT-Plus and the contribution of the new TB2 antigen tube. QFT-Plus results were collected from clinical laboratories in Sweden and linked to incident active TB within 3 to 24 months using the national TB registry. Among QFT-Plus results from 58,539 patients, 83% were negative (<0.20 IU/ml), 2.4% were borderline negative (0.20 to 0.34 IU/ml), 3.4% were borderline positive (0.35 to 0.99 IU/ml), 9.6% were positive (≥1.0 IU/ml), and 1.6% were indeterminate. Follow-up tests after initial borderline results were negative (<0.20 IU/ml) in 38.3%, without any cases of incident active TB within 2 years. Applying the 0.35-IU/ml cutoff, 1.5% of TB1 and TB2 results were discrepant, of which 52% were within the borderline range. A TB2 result of ≥0.35 IU/ml with a TB1 result of <0.20 IU/ml was found in 0.4% (231/58,539) of all included baseline QFT-Plus test results, including 1.8% (1/55) of incident TB cases. A borderline range for QFT-Plus is clinically useful as more than one-third of those with borderline results are convincingly negative upon retesting, without developing incident active TB. The TB2 tube contribution to LTB diagnosis appears limited.</p>}}, author = {{Wikell, A. and Jonsson, J. and Dyrdak, R. and Henningsson, A. J. and Eringfält, A. and Kjerstadius, T. and Hålldin, E. and Baqir, H. and Kholod, V. and Sturegård, E. and Bruchfeld, J. and Schön, T.}}, issn = {{1098-660X}}, keywords = {{active tuberculosis; borderline-range results; interferon gamma release assay; latent tuberculosis; Quantiferon Plus}}, language = {{eng}}, month = {{11}}, number = {{12}}, pages = {{0137021--0137021}}, publisher = {{American Society for Microbiology}}, series = {{Journal of Clinical Microbiology}}, title = {{The Impact of Borderline Quantiferon-TB Gold Plus Results for Latent Tuberculosis Screening under Routine Conditions in a Low-Endemicity Setting}}, url = {{http://dx.doi.org/10.1128/JCM.01370-21}}, doi = {{10.1128/JCM.01370-21}}, volume = {{59}}, year = {{2021}}, }