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PPD skin test - Risks

Alternative Names

Purified protein derivative standard; TB skin test; Tuberculin skin test

What the risks are:

There is a very small risk of severe redness and swelling of the arm in people who have had a previous positive PPD test and who have the test again. There also have been a few cases of this reaction in people who have not been tested before.

Special considerations:

A positive skin test does not necessarily mean that a person has active tuberculosis. More tests will be done to check whether there is active disease.

Many people who were born outside the United States may have had a vaccine called "BCG," which can lead to a false-positive test result. However, many experts believe that a past BCG vaccination should not change the PPD result when the test is done 15 years after the vaccination.

Tuberculosis in the kidney

Tuberculosis in the lung

Positive PPD skin test

PPD skin test

Reviewed last on: 9/28/2008
David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and Jatin M. Vyas, PhD, MD, Instructor in Medicine, Harvard Medical School, Assistant in Medicine, Division of Infectious Disease, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

References

Centers for Disease Control and Prevention. Questions and answers about TB. 2007. Accessed September 28, 2008.

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