Tuberculosis

There are two kinds of screening tests for TB: the Mantoux tuberculin skin test (TST) and the blood test, called the interferon gamma release assay (IGRA).

For the TST, a healthcare provider will inject a small amount of a substance called purified protein derivative (PPD) under the skin of your forearm. After two to three days, you must go back to the healthcare provider, who will look at the injection site.

For the IGRA, a healthcare provider will draw blood and send the sample to the lab.

Further tests to determine if an infection is active or if your lungs are infected include:

• Lab tests on sputum and lung fluid.
• Chest X-ray.
• Computed tomography (CT) scans.

How do I know if I should get tested for tuberculosis?

You may want to get tested for TB if:

• You are a resident or employee in group settings where the risk is high, such as jails, hospices, skilled nursing facilities, shelters and other healthcare facilities.
• You work in a mycobacteriology laboratory.
• You’ve been in contact with someone who’s known or suspected to have TB disease.
• Your body’s resistance to illness is low because of a weak immune system.
• You think you might already have TB disease and have symptoms.
• You’re from a region or have lived in a region where TB disease is prevalent, such as Latin America, the Caribbean, Africa, Asia, Eastern Europe and Russia.
• You’ve injected recreational drugs.
• Your healthcare provider recommends testing.

Others who are at risk for TB include:

• People with immature or impaired immune systems, such as babies and children.
• People with kidney disease, diabetes, or other chronic (long-term) illness.
• People who have received organ transplants.
• People being treated with chemotherapy for cancer or other types of treatments for immune system disorders.

The incidence rates for minority groups in the U.S. are higher than the incidence rates for whites.