Skin Test for Tuberculosis
October 20, 2013
The skin test for tuberculosis tells the doctor whether or not you have, or have had, tuberculosis (TB). Caused by the bacterium Mycobacterium tuberculosis , TB is a serious disease of the lungs and respiratory system and can reach other organs of the body.
To find out if you have, or have had, tuberculosis, a small amount of non-infectious proteins of the bacterium is introduced under the skin of the arm. Reaction to these proteins means that you have been exposed to the bacteria causing TB.
When the review is undertaken there?
Your doctor will determine the timing and frequency of the review.
You can ask this test to people who come into contact with someone who has been diagnosed with active TB, or those who have just arrived as an immigrant or visitor, a country with a high incidence TB. This test is also in case of weakened immune system (eg. Following organ transplantation or infection by the human immunodeficiency virus [HIV], or because of AIDS) and in people who have to start taking medication associated with an increased weakening of the immune system or infection by the bacterium responsible for tuberculosis risk.
Some employers require new employees pass this test before taking certain jobs. In the area of health, for example, may require workers to take the test each year.
The doctor uses this test to see if you have or have ever had TB, or if you have been exposed to the bacteria that causes this disease. This is a serious disease that may cause death if it is not treated with the appropriate medication.
Risks and precautions
Although this test is usually harmless, it happens that some people react strongly to the antigens used in the test, causing swelling and pain at the injection site. If necessary, contact your doctor immediately.
What will happen?
A qualified healthcare professional disinfects an area on your forearm. A small amount of TB protein (called antigens or purified protein derivative [PPD]) is injected under the skin. A technician can circle the area to clearly indicate where the proteins were injected.
Most people feel nothing, or only slight discomfort during the test. It is normal to see a drop of blood appear at the injection site, simply remove it gently with a compress.