Tuberculin testing: placement and interpretation.

1. The Mantoux skin test is the currently accepted standard for determination of infection with Mycobacterium tuberculosis. It is less than 100% sensitive and specific; however, no better method currently exists. 2. Placement and interpretation of the tuberculin skin test should be provided by health practitioners who are qualified as a result of education and experience. 3. Always produce a "wheal" when administering a tuberculosis (TB) skin test. If a significant amount of the dose leaks from the injection site or the injection is administered subcutaneously, the test should be repeated immediately at another site. 4. Induration, not erythema, should be considered in interpreting the TB skin test. The absence of induration with erythema greater than 10 mm in diameter may indicate the injection was made too deeply and retesting is indicated. 5. A history of BCG vaccination is not a contraindication to PPD skin testing. The larger the reaction to PPD, the greater the probability of TB infection.