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What is a TB Skin Test?
The tuberculin skin test consists of the injection of a small amount of purified protein derivative (PPD) from the organism that causes tuberculosis into the surface layers of the skin of the forearm. The PPD solution is completely harmless and contains no live tuberculosis organisms. The TB test is safe for people of all ages and is safe for women who are pregnant or nursing.
What Does a TB Skin Test Show?
Individuals who have at some time in their life been exposed to a bacteria of the Mycobacter Family (M. Tuberculosis is only one of many different mycobacteria) may have a positive reaction to the TB skin test. A positive reaction consists of swelling at the site of the injection and will be evaluated by the Health Department. A positive skin test does not necessarily mean that you have tuberculosis.
Who Should Not Have a TB Skin Test?
People who have had a positive reaction to a previous TB Skin Test
People who are currently receiving corticosteroid or immunosuppressive drugs
People who have received a measles, mumps or rubella vaccination within the past 30 days
Two Step Testing
Some people who were infected with M. tuberculosis many years ago will not react to the first PPD skin test that they receive, but will have a positive reaction when given another test at a later date. This is known as the "booster phenomenon" and may cause the second PPD to be misinterpreted as new tuberculosis infection. Anyone who is required to undergo annual or periodic PPD skin testing needs to have a two-step test the first time that they are tested. Two-step testing consists of 2 PPD skin tests separated by 1-3 weeks. You are only required to complete the two step procedure once; subsequent testing need only consist of one skin test.
Are There Any Side Effects From This Test?
Pain, itching, or a blister-like lesion may occur at the testing site in highly sensitive individuals.
You Must Return to Have Your Skin Test Read
Your skin test must be read 48 to 72 hours after it was administered; if you do not return within this time frame, the PPD will have to be repeated. Our schedule for PPD reading in Port Angeles is as follows: |
