Tuberculosis is a disease of the lungs that spreads from person to person by coughing, sneezing or speaking. Untreated active tuberculosis is a serious public health threat.
TB infection is more common than active TB, and has no symptoms, but requires treatment to prevent further development of the disease.
What is TB?
Tuberculosis is a bacterial infection found most often in the lungs, but can spread to other parts of the body. Untreated, it can destroy lung tissue and make breathing difficult or impossible. TB is a particular public health concern because it can spread easily through the air when a person with TB disease speaks, coughs or sneezes.
A person must be exposed (share air) with someone who has TB disease to become infected. Not everyone that is exposed becomes infected. Those that do become infected cannot spread TB to others unless their infection progresses to TB disease.
TB infection can be treated to help prevent progression to TB disease. TB disease usually occurs when the immune system of the infected person weakens, either through illness, age, medication or other causes. While TB infection is not contagious, it is very important to identify and treat infection before it can advance to TB disease. A person with TB infection has no signs or symptoms and does not feel sick. The only way to know whether you are infected is to have a TB test.
A person with TB disease typically is sick or has symptoms. Common symptoms include weight loss, loss of appetite, night sweats, weakness and fatigue. TB disease can be spread to others. If not treated correctly, TB disease can cause death.
For a person to become infected a fairly long or repeated exposure is often required. The people most likely to become infected are contacts of TB disease cases and persons living in or traveling to countries where TB is prevalent.
An estimated 10-15 million U. S. residents and one-third of the world’s population are currently infected with TB. A blood test called an Interferon Gamma Release Assay (IGRA) is the preferred test to identify TB infection.
Is TB infection dangerous?
TB infection does not cause sickness and has no symptoms. Persons with TB infection cannot spread the disease to others. A skin test or blood test can detect the presence of TB infection. If left untreated, TB infection can progress to TB disease.
How can I be tested for TB?
You can get a TB skin test or blood test at a local health clinic or your doctor's office. The tests are quick and simple, and give results in only a few days.
Who should be tested?
You should get a TB test if:
- You have spent time with a person who has active TB.
- You have the symptoms of TB: coughing for more than two weeks, pain in the chest, coughing of blood, and fatigue.
- You have a chronic disease such as diabetes, or another condition that weakens the immune system.
- You have lived in a foreign country where TB is common.
- You have lived or worked in a place where TB is common: migrant farm camps, prisons, homeless shelters or other crowded places where disease can spread.
- You use drugs injected with needles that may not be sterile.
- You have HIV infection.
- You are being evaluated for treatment with immunosuppressive drugs such as TnF inhibitors for arthritis
More About Testing
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TB and HIV/AIDS
Fact sheet from the CDC
Reports, fact sheets, brochures and links.
- TB Certification
- TB Co-Infections
- TB Testing