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Publication Details
AFRICAN RESEARCH NEXUS
SHINING A SPOTLIGHT ON AFRICAN RESEARCH
biochemistry, genetics and molecular biology
Short-term reproducibility of a commercial interferon gamma release assay
Clinical and Vaccine Immunology, Volume 16, No. 8, Year 2009
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Description
Interferon gamma release assays (IGRAs) have been shown to be sensitive and highly specific for the detection of immune memory against Mycobacterium tuberculosis. Little is known about the reproducibility and within-person variability of these assays. Various aspects of short-term reproducibility of a commercial IGRA, the QuantiFERON-TB Gold In-Tube (QFT-IT) assay, were assessed. The QFT-IT assay was performed twice within 3 days in 27 health care workers in Cape Town, South Africa. Two sets of tests were performed by different operators on day 1, and one set was performed on day 3. Aspects such as interoperator, intraoperator, day-to-day variability, and test-retest variability as well as different the storage methods of plasma were investigated. Seventeen of 27 (63%) of participants had at least one positive QFT-IT text; six had discordant results. The agreement of all aspects studied was high, with kappa values between 0.82 and 1.00 for dichotomous measures, and interclass correlations (ICC) of 0.809 to 0.965 were observed for continuous gamma interferon (IFN-γ) measures. The variability of the magnitude of response was highest comparing measures obtained from individuals on different days (ICC of 0.809). The magnitude of the IFN-γ responses between assays performed for individual participants was variable, with ranges from 0.03 to 11 IU/ml, resulting is discordant results for five participants. The results indicate that the QFT-IT assay is a robust and highly reproducible assay. Considerable intraindividual variability occurs in the magnitude of IFN-γ responses, which may influence the interpretation of serial measures. Copyright © 2009, American Society for Microbiology. All Rights Reserved.
Authors & Co-Authors
Detjen, Anne K.
South Africa, Stellenbosch
Stellenbosch University
Loebenberg, L.
South Africa, Stellenbosch
Stellenbosch University
Grewal, Harleen M.S.
Norway, Bergen
Universitetet I Bergen
Stanley, Kim
South Africa, Stellenbosch
Stellenbosch University
Gutschmidt, Andrea
South Africa, Stellenbosch
Stellenbosch University
Kruger, C.
South Africa, Stellenbosch
Stellenbosch University
Du Plessis, Nelita M.
South Africa, Stellenbosch
Stellenbosch University
Kidd, Martin
South Africa, Stellenbosch
Stellenbosch University
Beyers, Nulda
South Africa, Stellenbosch
Stellenbosch University
Walzl, Gerhard
South Africa, Stellenbosch
Stellenbosch University
Hesseling, Anneke Catharina
South Africa, Stellenbosch
Stellenbosch University
Statistics
Citations: 78
Authors: 11
Affiliations: 2
Identifiers
Doi:
10.1128/CVI.00168-09
ISSN:
15566811
e-ISSN:
1556679X
Research Areas
Infectious Diseases
Study Locations
South Africa