What Is a Positive Skin Test?

Positive skin test: This means the person's body was infected with TB bacteria. Additional tests are needed to determine if the person has latent TB infection or TB disease. Negative skin test: This means the person's body did not react to the test, and that latent TB infection or TB disease is not likely.

What happens if you have a positive 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. To be sure, your doctor will examine you and give you a chest x-ray.

What does positive PPD skin test mean?

The most commonly used skin test to check for TB is the PPD — purified protein derivative. If you have a positive PPD, it means you have been exposed to a person who has tuberculosis and you are now infected with the bacteria (mycobacterium tuberculosis) that causes the disease.