From latent to active TB: are IGRAs of any use?

• Published in: Thorax Vol. 71; no. 7; pp. 585 - 586
• Main Author: Lim, Wei Shen
• Format: Journal Article
• Language: English
• Published: England BMJ Publishing Group LTD 01.07.2016
• Subjects: Antigens; Interferon; Studies; Tuberculosis; Tuberculosis
• ISSN: 0040-6376; 1468-3296
• DOI: 10.1136/thoraxjnl-2016-208955

Incorporation bias (when the diagnostic test under consideration is used to determine the outcome) and partial verification bias (when individuals with positive tests are more likely to be subject to a 'gold standard' diagnostic) may also have influenced results. 8 These limitations aside, the study by Hermansen et al provides valuable information on the test characteristics of the QFT assay as it is used operationally and complements results from two other large European studies that have been published recently; Zellweger et al 9 reported a prospective cohort study conducted by the TB Network European Trials Group involving 5020 contacts of TB index cases from 10 countries, while Sloot et al 10 from Amsterdam reported a 10-year retrospective cohort study of 9332 contacts of pulmonary TB (see table 1 for summary of results). Some evidence suggests that chemoprophylaxis completion rates are inversely associated with duration of therapy (6-month isoniazid vs 3-month or 4-month rifampicin containing regimens) and that non-adherence is associated with higher risks of developing active TB compared with individuals who complete treatment. 12 13 Improved diagnostics, better therapeutic agents with fewer adverse effects and shorter treatment regimens are all needed.