Seasonal variation in the performance of QuantiFERON-TB Gold In-Tube assays used for the diagnosis of tuberculosis infection

• Published in: Tuberculosis (Edinburgh, Scotland) Vol. 110; pp. 26 - 29
• Main Authors: Tebruegge, Marc, Curtis, Nigel, Clifford, Vanessa, Fernandez-Turienzo, Cristina, Klein, Nigel, Fidler, Katy, Mansour, Salah, Elkington, Paul, Morris-Jones, Stephen
• Format: Journal Article
• Language: English
• Published: Scotland Elsevier Ltd 01.05.2018; Elsevier Science Ltd
• Subjects: Assaying; Autumn; Bioassays; Diagnosis; Diagnostic systems; Environmental factors; Humans; Indeterminate; Infections; Interferon; Interferon-gamma release assay; Interferon-gamma Release Tests - methods; Interferon-gamma Release Tests - standards; Medical diagnosis; Product quality; Retrospective Studies; Seasonal variations; Seasonality; Seasons; Specimen Handling - methods; Spring (season); Summer; Temperature; Tuberculosis; Tuberculosis - diagnosis; Winter; γ-Interferon; Tuberculosis; Interferon-gamma release assay; Performance; Indeterminate; Seasonality
• ISSN: 1472-9792; 1873-281X
• DOI: 10.1016/j.tube.2018.03.002

This study aimed to determine whether there are seasonal changes in the performance of QuantiFERON-TB Gold In-Tube (QFT-GIT) assays, an interferon-gamma release assay widely used for the diagnosis of tuberculosis infection. Results of 31,932 QFT-GIT assays performed at a large independent, accredited diagnostic service provider in London, UK over a 4.5-year-period were analysed. The proportion of positive results was significantly lower in autumn (14.8%) than in spring (16.0%; p = 0.0366) and summer (17.5%; p < 0.0001), but similar to winter (15.2%; p = 0.4711). The proportion of indeterminate results was significantly higher in autumn (8.2%) than in spring (6.2%; p < 0.0001), summer (4.8%; p < 0.0001), and winter (6.2%; p < 0.0001). The highest proportions of indeterminate results were observed in October (8.4%) and November (8.8%), the lowest in June (4.5%). Our data show that significant seasonal variation occurs in the performance of QFT-GIT assays in a temperate climate setting. Potential underlying mechanisms, including host and environmental factors, are discussed.