PPD skin test

Injury	Disease	Nutrition	Poison

Symptoms	Surgery	Test	Special Topic

Tuberculosis in the kidney

Tuberculosis in the lung

Positive ppd skin test

PPD skin test

Definition:

The purified protein derivative (PPD) is an antigen used to aid in the diagnosis of tuberculosis infection. An infection with the bacteria that causes tuberculosis frequently leads to a sensitivity to these antigens.

Alternative Names:

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

How the test is performed:

The test site (usually the forearm) is cleansed. The PPD extract is then injected into the most superficial layer under the skin resulting in a blister on the skin.

Because the reaction will take 48 - 72 hours to develop, you must return to your health care provider within that time for a proper evaluation of the test site. This will determine whether you have had a significant reaction to the PPD test. A reaction is measured in millimeters of induration (hard swelling) at the site.

How to prepare for the test:

There is no special preparation for this test. Inform your health care provider if you have ever had a positive PPD skin test. If so, you should not have a repeat PPD test. Notify your health care provider if you are taking certain drugs such as steroids or have a medical condition that can affect your immune system such as cancer. Your PPD may be falsely negative or the standards for interpreting a reaction may be different.

How the test will feel:

There will be a brief sting as a needle is inserted just below the skin surface.

Why the test is performed:

The test is performed to evaluate infection with tuberculosis.

Review Date: 6/10/2005
Reviewed By: Eleftherios Mylonakis, M.D., Division of Infectious Disease, Massachusetts General Hospital, Boston, MA. Review provided by VeriMed Healthcare Network.

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. Copyright 2004 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.