Related Experiment Videos
Reading the tuberculin skin test. Who, when, and how?
1Department of Internal Medicine, University of South Florida College of Medicine, Tampa 33612.
Archives of Internal Medicine
|November 1, 1988
Summary
The 24-hour induration from purified protein derivative (PPD) tests is valuable for screening healthy workers. However, patient self-readings are unreliable, and pen test results need careful interpretation.
Area of Science:
- Immunology
- Public Health
- Infectious Disease
Background:
- Tuberculosis screening relies on tuberculin skin testing (TST).
- Accurate interpretation of TST results is crucial for effective tuberculosis control.
- Standardized methods for TST administration and reading are essential.
Purpose of the Study:
- To evaluate the predictive value of 24-hour induration measurements in purified protein derivative (PPD) testing.
- To assess the accuracy of patient self-reading of TST results.
- To compare the pen and palpation methods for TST induration measurement.
Main Methods:
- Prospective study of 806 healthy health workers.
- Administered 5 tuberculin units of PPD via Mantoux technique.
- Induration measured by trained readers at 24 and 48-72 hours; patients also self-read results.
Main Results:
- 24-hour induration strongly predicted 48-72 hour findings.
- Patient self-readings were consistently inaccurate.
- Significant differences observed between pen and palpation methods, especially in the 5-14 mm range.
Conclusions:
- 24-hour PPD induration is a useful indicator in screening healthy populations.
- Clinical decisions should primarily rely on 48-72 hour readings by trained personnel.
- Patient self-interpretation of TST results is not recommended for clinical decision-making.