Use of a T cell interferon gamma release assay in the investigation for suspected active tuberculosis in a low prevalence area.
Winqvist, Niclas LU ; Björkman, Per LU
; Norén, Ann
and Miörner, Håkan
LU
(2009)
In BMC Infectious Diseases
9(Jul 3).
- Abstract
- BACKGROUND: In settings with low background prevalence of tuberculosis (TB) infection, interferon-gamma release assays (IGRA) could be useful for diagnosing active TB. This study aims to evaluate the performance of QuantiFERON-TB Gold (QFT-G) in the investigation for suspected active TB, with particular attention to patients originating in high-incidence countries. Furthermore, factors associated with QFT-G results in patients with active TB were assessed. METHODS: From patients investigated for clinically suspected active TB, blood was obtained for QFT-G testing, in addition to routine investigations. Positive (PPV) and negative (NPV) predictive values for QFT-G were calculated, comparing patients with confirmed TB and those with other... (More)
- BACKGROUND: In settings with low background prevalence of tuberculosis (TB) infection, interferon-gamma release assays (IGRA) could be useful for diagnosing active TB. This study aims to evaluate the performance of QuantiFERON-TB Gold (QFT-G) in the investigation for suspected active TB, with particular attention to patients originating in high-incidence countries. Furthermore, factors associated with QFT-G results in patients with active TB were assessed. METHODS: From patients investigated for clinically suspected active TB, blood was obtained for QFT-G testing, in addition to routine investigations. Positive (PPV) and negative (NPV) predictive values for QFT-G were calculated, comparing patients with confirmed TB and those with other final diagnoses. QFT-G results in TB patients originating from countries with intermediate or high TB incidence were compared with QFT-G results from a control group of recently arrived asymptomatic immigrants from high-incidence countries. Factors associated with QFT-G outcome in patients with confirmed TB were assessed. RESULTS: Among 141 patients, 41/70 (58.6%) with confirmed TB had a positive QFT-G test, compared to 16/71 (22.6%) patients with other final diagnoses, resulting in overall PPV of 71.9% and NPV of 67.6%. For patients with pulmonary disease, PPV and NPV were 61.1% and 67.7%, respectively, and 90.5% and 66.7% for subjects with extrapulmonary manifestations. Comparing patients from high-incidence countries with controls yielded a PPV for active TB of 76.7%, and a NPV of 82.7%. Patients with confirmed TB and positive QFT-G results were characterized by a lower median peripheral white blood cell count (5.9 x 10(9)/L vs. 8.8 x 10(9)/L; P < 0.001) and a higher median body mass index (22.7 vs. 20.7; P = 0.043) as compared to QFT-G-negative TB patients. CONCLUSION: The overall PPV and NPV of QFT-G for identifying active TB were unsatisfactory, especially for pulmonary disease. Thus, the usefulness of QFT-G for this purpose is questionable. However, a high PPV was observed for extrapulmonary TB and QFT-G might be considered in the diagnostic process in this situation. The PPV and NPV for identifying active TB among persons originating from regions with high-and intermediate TB incidence was similar to that observed in subjects originating in the low-incidence region. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/1453421
- author
- Winqvist, Niclas
LU
; Björkman, Per
LU
; Norén, Ann
and Miörner, Håkan
LU
- organization
- publishing date
- 2009
- type
- Contribution to journal
- publication status
- published
- subject
- in
- BMC Infectious Diseases
- volume
- 9
- issue
- Jul 3
- article number
- 105
- publisher
- BioMed Central (BMC)
- external identifiers
-
- wos:000268569600001
- pmid:19575781
- scopus:68049138081
- ISSN
- 1471-2334
- DOI
- 10.1186/1471-2334-9-105
- language
- English
- LU publication?
- yes
- id
- a1a410c9-6cc7-43f8-aee0-d828fcb386eb (old id 1453421)
- alternative location
- http://www.ncbi.nlm.nih.gov/pubmed/19575781?dopt=Abstract
- date added to LUP
- 2016-04-04 09:34:50
- date last changed
- 2025-04-04 15:13:51
@article{a1a410c9-6cc7-43f8-aee0-d828fcb386eb,
abstract = {{BACKGROUND: In settings with low background prevalence of tuberculosis (TB) infection, interferon-gamma release assays (IGRA) could be useful for diagnosing active TB. This study aims to evaluate the performance of QuantiFERON-TB Gold (QFT-G) in the investigation for suspected active TB, with particular attention to patients originating in high-incidence countries. Furthermore, factors associated with QFT-G results in patients with active TB were assessed. METHODS: From patients investigated for clinically suspected active TB, blood was obtained for QFT-G testing, in addition to routine investigations. Positive (PPV) and negative (NPV) predictive values for QFT-G were calculated, comparing patients with confirmed TB and those with other final diagnoses. QFT-G results in TB patients originating from countries with intermediate or high TB incidence were compared with QFT-G results from a control group of recently arrived asymptomatic immigrants from high-incidence countries. Factors associated with QFT-G outcome in patients with confirmed TB were assessed. RESULTS: Among 141 patients, 41/70 (58.6%) with confirmed TB had a positive QFT-G test, compared to 16/71 (22.6%) patients with other final diagnoses, resulting in overall PPV of 71.9% and NPV of 67.6%. For patients with pulmonary disease, PPV and NPV were 61.1% and 67.7%, respectively, and 90.5% and 66.7% for subjects with extrapulmonary manifestations. Comparing patients from high-incidence countries with controls yielded a PPV for active TB of 76.7%, and a NPV of 82.7%. Patients with confirmed TB and positive QFT-G results were characterized by a lower median peripheral white blood cell count (5.9 x 10(9)/L vs. 8.8 x 10(9)/L; P < 0.001) and a higher median body mass index (22.7 vs. 20.7; P = 0.043) as compared to QFT-G-negative TB patients. CONCLUSION: The overall PPV and NPV of QFT-G for identifying active TB were unsatisfactory, especially for pulmonary disease. Thus, the usefulness of QFT-G for this purpose is questionable. However, a high PPV was observed for extrapulmonary TB and QFT-G might be considered in the diagnostic process in this situation. The PPV and NPV for identifying active TB among persons originating from regions with high-and intermediate TB incidence was similar to that observed in subjects originating in the low-incidence region.}},
author = {{Winqvist, Niclas and Björkman, Per and Norén, Ann and Miörner, Håkan}},
issn = {{1471-2334}},
language = {{eng}},
number = {{Jul 3}},
publisher = {{BioMed Central (BMC)}},
series = {{BMC Infectious Diseases}},
title = {{Use of a T cell interferon gamma release assay in the investigation for suspected active tuberculosis in a low prevalence area.}},
url = {{http://dx.doi.org/10.1186/1471-2334-9-105}},
doi = {{10.1186/1471-2334-9-105}},
volume = {{9}},
year = {{2009}},
}