Fluctuating Behavior and Influential Factors in the Performance of the QuantiFERON-TB Gold In-Tube Assay in the Diagnosis of Tuberculosis.
BACKGROUND
The QuantiFERON-TB Gold In-Tube (QFT-GIT) is a newly developed but widely used interferon-γ release assay for diagnosing tuberculosis (TB). However, research has not determined whether age or the use of an immune suppressive or anti-TB treatment influences this assay's ability to detect TB. We assessed the QFT-GIT diagnostic performance for active tuberculosis (ATB) in children and adults in an endemic country and explored the effects of glucocorticoids and anti-TB therapy on the diagnostic value of the QFT-GIT.


METHODS
A total of 60 children and 212 adults with suspected ATB were evaluated with the QFT-GIT. The association between the QFT-GIT diagnostic value and pretreatment factors was qualitatively and quantitatively assessed.


RESULTS
The sensitivity of the QFT-GIT was 83.9% (95% CI 66.3%-94.6%) in children, and 73.7% (95% CI 57.8%-85.2%) in adults. Glucocorticoids affected the mitogen-stimulated response in both children and adults. In subjects undergoing glucocorticoid pretreatment, 25.0% of the children presented with false-negative QFT-GIT results, 28.6% of adults presented with indeterminate results. For subjects pre-treated with anti-TB drugs, 44.4% presented with false-negative QFT-GIT results.


CONCLUSIONS
The QFT-GIT has higher sensitivity and specificity in children than adults. Glucocorticoid treatment negatively impacts the diagnostic value of the QFT-GIT in all age groups. Anti-TB treatment decreases the sensitivity of the QFT-GIT. Therefore, we recommend that the QFT-GIT assay be performed before TB-specific treatment is initiated and the test should not be used on people undergoing immunosuppression treatment, regardless of their age. A quantitative analysis of the QFT-GIT could be useful for assessing and monitoring TB-specific and non-specific immunity during conversion of the disease.
Department of Infectious Diseases, Huashan Hospital, Fudan University, Shanghai, China.
Lei
L
Bao
Department of Infectious Diseases, Huashan Hospital, Fudan University, Shanghai, China; Department of Tuberculosis Disease, Shanghai Public Health Clinical Center, Fudan University, Shanghai, China.
Tao
T
Li
Department of Infectious Diseases, Huashan Hospital, Fudan University, Shanghai, China.
Ni
N
Diao
Department of Infectious Diseases, Huashan Hospital, Fudan University, Shanghai, China.
Yaojie
Y
Shen
Department of Infectious Diseases, Huashan Hospital, Fudan University, Shanghai, China.
Lingyun
L
Shao
Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America.
Ying
Y
Zhang
Department of Tuberculosis Disease, Shanghai Public Health Clinical Center, Fudan University, Shanghai, China.
Shuihua
S
Lu
Department of Infectious Diseases, Huashan Hospital, Fudan University, Shanghai, China; Institutes of Biomedical Sciences, Fudan University, Shanghai, China.
Wenhong
W
Zhang
D000328:Adult; D001681:Biological Assay / Q000379:methods*; D002675:Child, Preschool; D005188:False Negative Reactions; D005260:Female; D005938:Glucocorticoids / Q000737:chemistry; D006046:Gold / Q000276:immunology*; D006801:Humans; D007113:Immunity, Innate / Q000276:immunology; D059425:Interferon-gamma Release Tests / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011933:Reagent Kits, Diagnostic; D012680:Sensitivity and Specificity; D014374:Tuberculin Test / Q000379:methods*; D014376:Tuberculosis / Q000175:diagnosis*
D005938:Glucocorticoids; D011933:Reagent Kits, Diagnostic; D006046:Gold