Authors: Farhat, M.¹; Greenaway, C.²; Pai, M.³; Menzies, D.⁴

Source: The International Journal of Tuberculosis and Lung Disease, Volume 10, Number 11, November 2006 , pp. 1192-1204(13)

Publisher: International Union Against Tuberculosis and Lung Disease

Abstract:

BACKGROUND: Despite certain drawbacks, the tuberculin skin test (TST) remains in widespread use. Important advantages of the TST are its low cost, simplicity and interpretation based on extensive published literature. However, TST specificity is reduced by bacille Calmette-Guérin (BCG) vaccination and exposure to non-tuberculous mycobacteria (NTM).

METHODS: To estimate TST specificity, we reviewed the published literature since 1966 regarding the effect of BCG vaccination and NTM infection on TST. Studies selected included healthy subjects with documented BCG vaccination status, including age at vaccination. Studies of NTM effect had used standardised NTM antigens in healthy subjects.

RESULTS: In 24 studies involving 240203 subjects BCG-vaccinated as infants, 20406 (8.5%) had a TST of 10+ mm attributable to BCG, but only 56/5639 (1%) were TST-positive if tested ≥10 years after BCG. In 12 studies of 12728 subjects vaccinated after their first birthday, 5314 (41.8%) had a false-positive TST of 10+ mm, and 191/898 (21.2%) after 10 years. Type of tuberculin test did not modify these results. In 18 studies involving 1169105 subjects, the absolute prevalence of false-positive TST from NTM cross-reactivity ranged from 0.1% to 2.3% in different regions.

CONCLUSIONS: The effect on TST of BCG received in infancy is minimal, especially ≥10 years after vaccination. BCG received after infancy produces more frequent, more persistent and larger TST reactions. NTM is not a clinically important cause of false-positive TST, except in populations with a high prevalence of NTM sensitisation and a very low prevalence of TB infection.

Keywords: tuberculin skin test; latent TB infection; atypical mycobacteria; environmental mycobacteria; non-tuberculous mycobacteria; BCG vaccination

Document Type: Review article

Affiliations: 1: Respiratory Epidemiology and Clinical Research Unit, Montreal Chest Institute, McGill University, Montreal, Quebec, Canada; and Massachusetts General Hospital, Harvard University, Boston, Massachusetts, USA 2: Respiratory Epidemiology and Clinical Research Unit, Montreal Chest Institute, McGill University, Montreal, Quebec, Canada; and Division of Infectious Disease and Microbiology, SMBD-Jewish General Hospital, McGill University, Montreal, Quebec, Canada 3: Respiratory Epidemiology and Clinical Research Unit, Montreal Chest Institute, McGill University, Montreal, Quebec, Canada; and Joint Departments of Epidemiology & Biostatistics and Occupational Health, McGill University, Montreal, Quebec, Canada 4: Respiratory Epidemiology and Clinical Research Unit, Montreal Chest Institute, McGill University, Montreal, Quebec, Canada

Publication date: 2006-11-01

More about this publication?

• The International Journal of Tuberculosis and Lung Disease publishes articles on all aspects of lung health, including public health-related issues such as training programmes, cost-benefit analysis, legislation, epidemiology, intervention studies and health systems research. The IJTLD is dedicated to the continuing education of physicians and health personnel and the dissemination of information on tuberculosis and lung health world-wide.

  Certain IJTLD articles are selected for translation into French, Spanish, Chinese or Russian. They are available on the Union website

• Editorial Board
• Information for Authors
• Subscribe to this Title
• ingentaconnect is not responsible for the content or availability of external websites

Related content

• In this: publication
• By this: publisher
• In this Subject: Internal Medicine
• By this author: Farhat, M. ;  Greenaway, C. ;  Pai, M. ;  Menzies, D.

Website © Publishing Technology. Article copyright remains with the publisher, society or author(s) as specified within the article.

• Terms and conditions
• Privacy policy
• Information for advertisers