Tuberculosis (TB) Disease: Only the Tip of the Iceberg
- There are two types of TB conditions: TB disease and latent TB infection.
- People with TB disease are sick from active TB germs. They usually have symptoms and may spread TB germs to others.
- People with latent TB infection do not feel sick, do not have symptoms, and cannot spread TB germs to others. But, if their TB germs become active, they can develop TB disease.
- Millions of people in the U.S. have latent TB infection. Without treatment, they are at risk for developing TB disease.
- DOWNLOAD: General Information: Tuberculosis English
- DOWNLOAD: La Tuberculosis: Información General Espanol
- Schedule a TB SKIN TEST, Click Here.
Listen to a Podcast about the Basic Tuberculosis Information:
In this podcast, Dr. Kenneth Castro, Director of the Division of Tuberculosis Elimination, discusses basic TB prevention, testing, and treatment information. Created: 3/12/2012 by National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention (NCHHSTP). Date Released: 3/12/2012. Series Name: CDC Featured Podcasts.
TB Skin Tests
Tuberculosis (TB) is a disease that is spread through the air from one person to another.
There are two kinds of tests that are used to determine if a person has been infected with TB bacteria: the tuberculin skin test and TB blood tests. A positive TB skin test or TB blood test only tells that a person has been infected with TB bacteria. It does not tell whether the person has latent TB infection (LTBI) or has progressed to TB disease. Other tests, such as a chest x-ray and a sample of sputum, are needed to see whether the person has TB disease.
Tuberculin skin test: The TB skin test (also called the Mantoux tuberculin skin test) is performed by injecting a small amount of fluid (called tuberculin) into the skin in 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. The health care worker will look for a raised, hard area or swelling, and if present, measure its size using a ruler. Redness by itself is not considered part of the reaction.
The skin test result depends on the size of the raised, hard area or swelling. It also depends on the person’s risk of being infected with TB bacteria and the progression to TB disease if infected.
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. A health care worker will then provide treatment as needed.
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.