What is TB?
Tuberculosis (TB) is caused by bacteria called Mycobacterium tuberculosis (M. tuberculosis). The bacteria, or germ, usually attack the lungs. TB germs can attack any part of the body, such as the kidney, spine, or brain.
There is good news. People with TB can be treated if they seek medical help.
How is TB spread?
TB is spread through the air from one person to another. The TB germs are spread into the air when a person with infectious TB disease of the lungs or throat coughs, speaks, or sings. People nearby may breathe in these TB germs and become infected.
When a person breathes in TB germs, the TB germs can settle in the lungs and begin to grow. From there, the TB germs can move through the blood to other parts of the body, such as the kidney, spine, or brain.
Who is at risk for getting TB?
Anyone can get TB. Some people have a higher risk of getting infected with TB:
- People who have contact with someone who has infectious TB disease
- People who were born in or who frequently travel to countries where TB disease is common, including Mexico, the Philippines, Vietnam, India, China, Haiti, Guatemala, and other countries with high rates of TB
- Health care workers and others who work or live in places at high risk for TB transmission, such as homeless shelters, jails, and nursing homes
What is Latent TB Infection (LTBI)?
In most people who breathe in TB germs and become infected, the body is able to fight the TB germs to stop them from growing. The TB germs become inactive, but they remain alive in the body and can wake up and become active later. This is called latent TB infection, or LTBI for short.
People with LTBI:
- Have no symptoms.
- Don’t feel sick.
- Can’t spread TB germs to others.
- Usually have a positive TB blood test or positive skin test reaction.
- May develop TB disease if they do not receive treatment for LTBI.
For this reason, people with LTBI should be treated to prevent them from developing TB disease. Treatment of LTBI is essential to controlling TB in the United States because it substantially reduces the risk that LTBI will progress to TB disease.
What is TB disease?
If the immune system can’t stop TB germs from growing, the TB germs begin to multiply in the body and cause TB disease. The TB germs attack the body, and if this occurs in the lungs, the TB germs can create a hole in the lung. Some people develop TB disease soon after becoming infected (within weeks) before their immune system can fight the TB germs. Other people have latent TB infection and may get sick years later, when their immune system becomes weak for another reason. Treating latent TB infection (LTBI) is effective in preventing TB disease.
People with TB disease in the lungs or throat can be infectious, meaning that they can pass TB germs to their family, friends, and others around them. People with TB in other parts of their bodies, such as the kidneys or spine, are usually not infectious.
People with TB disease are most likely to spread it to people they spend time with every day. This includes family members, friends, coworkers, or schoolmates.
People with TB disease need to take several medicines when they start treatment. After taking TB medicine for several weeks, a doctor will be able to tell TB patients when they are no longer able to spread TB germs to others. Most people with TB disease will need to take TB medicine for at least 6 months to be cured.
What are the symptoms of TB Disease?
Symptoms of TB disease depend on where in the body the TB germs are growing. TB disease in the lungs may cause the following symptoms:
- Cough (lasting longer than 3 weeks)
- Coughing up sputum (phlegm from inside the lungs) or blood
- Chest pain
- Fever
- Night Sweats
- Chills
- Loss of appetite
- Weakness or fatigue
- Weight loss
Symptoms of TB disease in other parts of the body may include the following:
- TB of the kidney may cause blood in the urine.
- TB meningitis may cause headache or confusion.
- TB of the spine may cause back pain.
- TB of the larynx may cause hoarseness.
What are the tests for TB infection?
There are two types of tests for TB infection: the TB blood test and the TB skin test. Your health care provider should choose which TB test to use. Generally, it is not recommended to use both a TB skin test and a TB blood test to test the same person.
TB Blood Tests
TB blood tests use a blood sample to find out if you are infected with TB germs. Two TB blood tests are approved by the U.S. Food and Drug Administration and are available in the United States:
- QuantiFERON®-TB Gold Plus (QFT-Plus)
- T-SPOT®.TB test (T-Spot)
You can get a TB blood test at the health department or at your doctor’s office. The health care provider will draw your blood and send it to a laboratory for analysis and results. If your health department uses a TB blood test, only one visit is required to draw blood for the test.
- A positive TB blood test means that you have been infected with TB germs. Additional tests are necessary to determine whether you have LTBI or TB disease.
- A negative TB blood test means that your blood did not react to the test and that you likely do not have TB infection.
TB Skin Test
The TB skin test may be used to find out if you are infected with TB germs. You can get a skin test at the health department or at your doctor’s office. A health care worker will inject a small amount of testing fluid (called tuberculin or PPD) into the skin on the lower part of your arm. After 2 or 3 days, you must return to have your skin test read by the health care worker. You may have swelling where the tuberculin was injected. The health care worker will measure this swelling and tell you if your reaction to the test is positive or negative.
- Positive skin test: This means the person’s body is infected with TB germs. Additional tests are needed to determine if the person has LTBI or TB disease.
- Negative skin test: This means the person’s body did not react to the test, and that LTBI or TB disease is not likely.
What if I have a positive test for TB infection?
If you have a positive reaction to the TB blood test or TB skin test, your doctor or nurse will do other tests to see if you have TB disease. These tests usually include a chest x-ray. They may also include a test of the sputum you cough up. Because TB germs may be found somewhere other than your lungs, your doctor or nurse may check your urine, take tissue samples, or do other tests. Without treatment, LTBI can progress to TB disease. If you have LTBI, you should be treated to prevent developing TB disease. If you have TB disease, you will need to take medicine to treat the disease.
If I have latent TB infection (LTBI), how can I avoid developing TB disease?
Without treatment, latent TB infection (LTBI) can progress to TB disease. If you have LTBI, you should be treated to prevent TB disease even if you do not feel sick. Treatment of LTBI is essential to preventing TB because it substantially reduces the risk that latent TB infection will progress to TB disease.
Treating latent TB infection is effective in preventing TB disease. There are several options for the treatment of LTBI. There have been advances in shortening the length of LTBI treatment from 6–9 months to 3–4 months. Short-course LTBI treatments are effective, are safe, and have higher completion rates than longer treatments.
If you have latent TB infection and you are in one of these high-risk groups, it is even more urgent that you take medicine so you don’t develop TB disease.
How is TB disease treated?
There is good news for people with TB disease! It can almost always be treated and cured with medicine. But the medicine must be taken as directed by your doctor or nurse.
If you have TB disease, you will need to take several different TB medicines. This is because there are many TB germs to be killed. Taking several TB medicines will do a better job of killing all the TB germs and preventing them from becoming resistant to the medicines. “Resistant” means that the medicine can no longer kill the TB bacteria.
The most common medicines used to treat TB disease are:
- Isoniazid (INH)
- Rifampin (RIF)
- Ethambutol (EMB)
- Pyrazinamide (PZA)
If you have TB disease of the lungs or throat, you may be infectious. You need to stay home from work or school so that you don’t spread TB germs to other people. After taking your medicine for a few weeks, you will feel better and you may no longer be infectious to others. Your doctor or nurse will tell you when you can return to work or school or visit with friends.
Having TB disease should not stop you from leading a normal life. People who are no longer infectious or feeling sick are often able to do the same things they did before they had TB disease. If you take your medicines as directed by your doctor or nurse, they should kill all the TB germs. This will keep you from becoming sick again.
How can I keep from spreading TB?
The most important way to keep from spreading TB is for people with infectious TB disease to take all medicines exactly as directed by a doctor or nurse. You also need to keep all your clinic appointments! Your doctor or nurse needs to see how you are doing. This often requires another chest x-ray or a test of the phlegm you may cough up. These tests will show whether the medicines are working. They will also show whether you can still give TB germs to others. Be sure to tell the doctor about anything you think is wrong.
If you are sick enough with TB disease to go to a hospital, you may be put in a special room. These rooms use air vents that keep TB germs from spreading to other rooms. People who work in these special rooms must wear a special face mask to protect themselves from TB germs. You must stay in the room so that you will not spread TB germs to other people.
If you are infectious while you are at home, there are things you can do:
- Take your medicines as directed. This is very important!
- Always cover your mouth with a tissue when you cough and dispose of the tissue.
- Do not go to work or school. Separate yourself from others and avoid close contact with anyone. Sleep in a bedroom away from other family members.
- Air out your room often to the outside of the building (if it is not too hot/cold outside). TB spreads in small closed spaces where air doesn’t move. Put a fan in your window to blow out (exhaust) air that may be filled with TB germs. Remember, TB is spread through the air. People cannot get infected with TB germs through handshakes, sitting on toilet seats, or sharing dishes and utensils with someone who has TB.
After you take the medicines for about 2 or 3 weeks, you may no longer be able to spread TB germs to others. Your doctor or nurse will tell you when you can return to work or school or visit with friends.
Remember, you will get well only if you take your medicines exactly as directed by your doctor or nurse.
Think about people who may have spent time with you, such as family members, close friends, and coworkers. The local health department may need to test them for TB infection. TB is especially dangerous for children and people infected with HIV. If infected with TB germs, these people need medicine right away to keep from developing TB disease.
For additional information about LTBI and TB disease, please visit www.cdc.gov/tb. Patient materials on LTBI and TB disease are also available in multiple languages at www.cdc.gov/tb/publications/culturalmaterials.htm and https://findtbresources.cdc.gov/.