TB is a preventable disease, even in those who have been exposed to an infected person. Skin testing for TB is used in high risk populations or in people who may have been exposed to TB, such as health care workers.

A positive skin test in a person without symptoms is a sign of TB exposure. Discuss preventive therapy with your doctor. People who have been exposed to TB should be skin tested immediately and have a follow-up test at a later date, if the first test is negative.

Prompt treatment is extremely important in controlling the spread of TB from those who have active TB disease to those who have never been infected with TB.

Some countries with a high incidence of TB give people a vaccination (called BCG) to prevent TB. However, the effectiveness of this vaccine is controversial and it is not routinely used in the United States.

Those who have had BCG may still be skin tested for TB.