Utility of QuantiFERON-TB Gold In-Tube assay in adult, pulmonary and extrapulmonary, active tuberculosis diagnosis.

Mohammed Azghay, Olivier Bouchaud, Frederic Mechaï, Pascale Nicaise, Olivier Fain, Jérôme Stirnemann,

International journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases, January 18, 2016

Tuberculosis remains a public health problem in France and the diagnosis of tuberculosis disease (TB) is sometimes difficult. The aim of our study was to analyse the contribution of Quantiferon - Gold In Tube® (QTF -GIT) in TB diagnosis.≤ABS-P≥Materials and Methods We retrospectively identified 60 patients hospitalized for TB, for whom QTF assays had been performed between June 2008 and June 2011 at the University Hospital (CHU) of Bondy in the north east of Paris. Clinical and laboratory data were collected. The sensitivity, specificity, predictive values ??and likelihood ratios of QTF were all calculated. We also compared the characteristics of patients testing positive with those testing negative, as well as the rates of QTF according to several different factors. The sensitivity of the QTF was 85% (95% CI 0.73 - 0.92), specificity 73.3% (95% CI 0.68 - 0.78). The Positive Predictive Value was 39.5% and the Negative Predictive Value 97.3%. The positive and negative likelihood ratios were, respectively, 3.2 and 0.20. In our population, the prevalence of TB was 15% (Pre-Test probability). After a positive test result, the probability of TB increased to 40% (Post-Positive probability test). After a negative test result, it decreased to 4.5% (Post-Negative probability test). The combination of the QTF test with the Tuberculin Skin Test (TST) brought no significant improvement in sensitivity. Factors significantly associated with a negative QTF result included older age, high CRP, a low rate of lymphocytes and immunosuppressant intake. The test value in quantitative terms was significantly higher in those with lymph node tuberculosis than with pulmonary tuberculosis, and in younger patients (< 40 years) than older patients (> 40 years old). On its own, QTF is an insufficient tool to confirm the diagnosis of tuberculosis disease. However, it may form part of an ensemble of tools in combination with clinical, biological and radiological measurements.

Copyright © 2016. Published by Elsevier Ltd.

Pubmed Link: 26780268

DOI: 10.1016/j.ijid.2016.01.004