A prospective longitudinal study evaluating a T-cell-based assay for latent tuberculosis infection in health-care workers in a general hospital in Beijing

• Published in: Chinese medical journal Vol. 126; no. 11; pp. 2039 - 2044
• Main Authors: ZHANG, Li-fan, LIU, Xiao-qing, ZHANG, Yao, DENG, Guo-hua, Pareek, Manish, Lalvani, Ajit
• Format: Journal Article
• Language: English
• Published: China Clinical Epidemiology Unit,Peking Union Medical College Hospital,Chinese Academy of Medical Sciences & Peking Union Medical College,Beijing 100730,China%Department of Infectious Diseases ,Peking Union Medical College Hospital,Chinese Academy of Medical Sciences & Peking Union Medical College,Beijing 100730,China%Tuberculosis Research Unit,Department of Respiratory Medicine,National Heart and Lung Institute,Imperial College London,St Mary's Campus,Norfolk Place,London,W21PG,United Kingdom 05.06.2013; Department of Infectious Diseases ,Peking Union Medical College Hospital,Chinese Academy of Medical Sciences & Peking Union Medical College,Beijing 100730,China
• Subjects: Adult; Female; Health Personnel; Hospitals, General; Humans; Latent Tuberculosis - diagnosis; Latent Tuberculosis - etiology; Latent Tuberculosis - immunology; Longitudinal Studies; Male; Pilot Projects; Prospective Studies; Risk Factors; Tuberculin Test; latent tuberculosis infection; T-SPOT.TB; exposure; tuberculin skin test; follow-up study
• DOI: 10.3760/cma.j.issn.0366-6999.20130355
• ISSN: 0366-6999; 2542-5641

The health-care workers (HCWs) are at high risk of acquiring infection with Mycobacterium tuberculosis. The objectives of this study were to compare the performance of the T-SPOT.TB and tuberculin skin test (TST) for latent tuberculosis infection (LTBI), evaluate diagnostic concordance and risk factors for LTBI, and observe the progression to active tuberculosis (TB) disease among HCWs in a general hospital in Beijing. The prospective cohort study enrolled HCWs in a tertiary general hospital in Beijing, China, to evaluate LTBI with T-SPOT.TB and TST. The subjects were evaluated every 12 months during the 60-month follow-up. Of 101 participating HCWs, 96 and 101 had valid TST and T-SPOT.TB results, respectively. Twenty-nine (28.7%, 95% confidence interval (CI), 19.9% - 37.5%) were defined as positive by T-SPOT.TB and 53 (55.2%, 95%CI, 45.2% - 64.9%) were defined as positive by TST (using a ≥ 10 mm cutoff). An agreement between the two tests was poor (57.3%, κ = 0.18, 95%CI, 0.01% - 0.52%). In multivariate analysis, direct exposure to sputum smear-positive TB patients was a significant risk factor for a positive T-SPOT.TB (OR 5.76; 95%CI 1.38 - 24.00). Pooled frequency of antigen-specific IFN-γ secreting T-cells for subjects who reported direct contact with sputum smear-positive TB patients was significantly higher than that for participants without direct contact (P = 0.045). One of 20 participants with positive result of T-SPOT.TB and TST developed active TB at 24-month follow-up. T-SPOT.TB is a more accurate, targeted method of diagnosing LTBI than TST.