Extent of Tuberculin Skin Testing Spot in Bacteriologically Verified Tuberculosis

Overview

Background.
Tuberculin skin test was evaluated in patients with bacteriologically verified tuberculosis notified in the Czech Republic during 2003 and 2004.  

Methods and Results.
Out of 1172 patients with bacteriologically verified tuberculosis altogether 28.8% were tuberculin-negative. The average value of tuberculin reaction in this cohort was 11.6 mm. Among 30-year-old patients with bacteriologically verified tuberculosis the number of tuberculin-negative individuals was statistically lower (14 %) in comparison with 70-year-old and older patients, where the prevalence of tuberculin-negative individuals was 42 %. Higher rate of tuberculin-negative individuals with bacteriologically verified tuberculosis was found among patients who were diagnosed with liver disease (42 % of tuberculin-negative) or malignant tumor (47 % of tuberculin-negative). Presented results show that in circumstances of the Czech Republic the tuberculin skin test can be used to follow up the spreading of tuberculosis infection in younger age groups without accompanying serious disease only.  

Conclusions.
The improvement of the diagnostics of latent tuberculosis infection can bring the routine introduction of new tests, e.g. Quantiferon-TB Gold or other methods.  

Key words:
tuberculin skin test, bacteriologically verified tuberculosis.