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TB Basics

These questions and answers are excerpted from Tuberculosis—Get the Facts! by CDC's Division of Tuberculosis Elimination. CDC also offers Basic Materials for Health Care Providers and Basic TB Facts for the public.

What is tuberculosis?

Tuberculosis (TB) is a disease that usually affects the lungs. TB sometimes affects other parts of the body, such as the brain, the kidneys, or the spine. TB disease can cause death if untreated.

How is TB spread?

TB germs are spread from person to person through the air. TB germs are put into the air when a person with TB disease of the lungs or throat coughs, sneezes, laughs, or sings. TB is NOT spread by sharing silverware or cups, sharing cigarettes, or sharing saliva when kissing someone.

What are the symptoms of TB?

People with TB disease often feel weak or sick, lose weight, have fever, and have night sweats. If their TB disease is in the lungs, they may also cough and have chest pain, and they might cough up blood. Other symptoms depend on what part of the body is affected.

What is the difference between TB disease and TB infection?

People with TB disease are sick from the large number of TB germs that are active in their body. They usually have one or more of the symptoms of TB disease. These people may pass the TB germs to others. TB disease can cause permanent body damage and death. Medicines which can cure TB disease are given to these people.

People with TB infection also have the germs that cause TB in their body. But they are not sick because there are not as many of the germs, and the germs lie dormant (sleeping) in their body. They cannot spread the germs to others. However, these people could develop TB disease in the future, especially if they are in one of the high-risk groups listed under "Who gets TB disease?" People with TB infection can take medicine to prevent them from developing TB disease.

Who gets TB disease?

Once a person has TB infection, he or she has a higher chance of getting TB disease if the person:

  • Has HIV infection.
  • Has been recently infected with TB germs (in the last 2 years).
  • Has other health problems, like diabetes, that make it hard for the body to fight germs.
  • Abuses alcohol or illegal drugs.
  • Was not treated correctly for TB infection in the past.

How can I tell if I have TB?

Get a TB skin test or blood test. If you have a positive reaction to either of the tests, you will probably be given other tests to see if you have TB infection or TB disease.

Where can I get a TB skin test or blood test?

You can get a TB skin test or blood test from your doctor or local health department.

What if the test is positive?

A positive skin test or blood test usually means that you have been infected with the TB germ. It does not necessarily mean that you have TB disease. Other tests, such as an X-ray or sputum sample, are needed to see if you have TB disease.

What should I do if I have TB infection or TB disease?

Get the required follow-up tests. Follow your doctor’s advice and take the medicine as prescribed. Today, both TB infection and TB disease can be treated and cured with medication.