What is in the tuberculin skin test?
During one visit to a doctor’s office or clinic, a tiny amount of tuberculin is injected under the skin, usually in the forearm. Tuberculin is a sterile extract purified protein derivative (PPD) made from the bacteria that cause TB. After receiving the injection, a small, pale bump will form at the site.
What is a positive tuberculin skin test?
The test is “positive” if there is a bump of a certain size where the fluid was injected. This means you probably have TB germs in your body. Most people with a positive TB skin test have latent TB infection.
How is tuberculin skin test done?
The TB skin test is performed by injecting a small amount of fluid (called tuberculin) into the skin on the lower part of the arm. A person given the tuberculin skin test must return within 48 to 72 hours to have a trained health care worker look for a reaction on the arm.
What is the purpose of a Mantoux skin test?
The Mantoux tuberculin skin test (TST) is one method of determining whether a person is infected with Mycobacterium tuberculosis. Reliable administration and reading of the TST requires standardization of procedures, training, supervision, and practice.
What procedures are performed if a patient has a positive reaction to a tuberculin skin test?
Patients who have a positive TST must receive a chest radiograph and undergo clinical evaluation for TB disease prior to starting treatment for LTBI, as described later in this chapter.
What happens if Mantoux test is positive?
If the Mantoux results are positive, then the doctor will ask for blood tests or X-ray of your chest. Also there could also be tests to check for infection through your sputum. Finally, urine or tissue samples can also be collected for testing if the doctor has diagnosed that the infection is spreading.
How big is a positive TB test?
An induration of 15 mm or more is considered positive in: Always considered positive in any person. Healthy individuals without any risk factors for TB.
Can you be allergic to TB skin test?
There is a very slight risk of having a severe reaction to the tuberculin skin test, especially if you have had tuberculosis (TB). An allergic reaction can cause a lot of swelling and pain at the site.