PPD skin test

You will need two visits to your health care provider's office for this test. At the first visit, the provider will clean an area of your skin, usually the inside of your forearm. You will get a small shot (injection) that contains PPD. The needle is gently placed under the top layer of skin, causing a bump (welt) to…

There is no special preparation for this test. Tell your provider if you have ever had a positive PPD skin test. If so, you should not have a repeat PPD test, except under unusual circumstances. Tell your provider if you have a medical condition or if you take certain medicines, such as steroids, which can affect your…

You will feel a brief sting as the needle is inserted just below the skin surface.

This test is done to find out if you have ever come in contact with the bacteria that cause TB. TB is an easily spread (contagious) disease. It most often affects the lungs. The bacteria can remain inactive (dormant) in the lungs for many years. This situation is called latent TB. Most people in the United States who…

A negative reaction usually means you have never been infected with the bacteria that cause TB. With a negative reaction, the skin where you received the PPD test is not swollen, or the swelling is very small. Interpreting the size of the swelling is different for children, people with HIV, and other high-risk groups.…

An abnormal (positive) result means you have been infected with the bacteria that cause TB. You may need treatment to lower the risk of the disease coming back (reactivation of the disease). A positive skin test does not mean that a person has active TB. More tests must be done to check whether there is active…

There is a very small risk for severe redness and swelling of the arm in people who have had a previous positive PPD test and who have the test again. Generally, people who have had a positive test in the past should not be retested. This reaction can also occur in a few people who have not been tested before.

Centers for Disease Control and Prevention website. Tuberculosis (TB). About tuberculosis. www.cdc.gov/tb/about/index.html . Reviewed December 19, 2023. Accessed June 25, 2024. Fitzgerald DW, Sterling TR, Haas DW. Mycobacterium tuberculosis. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's…