Key points
- Tuberculosis (TB) germs can live in the body for years without making you sick. This is called inactive TB or latent TB infection.
- People with inactive TB do not feel sick, do not have symptoms, and cannot spread TB germs to others.
- Without treatment, inactive TB can develop into active TB disease at any time and make you sick.
Overview
TB germs can live in the body without making you sick. This is called inactive TB or latent TB infection.
A person with inactive TB:
- Has a small amount of TB germs in their body that are alive but inactive.
- Has no TB symptoms and does not feel sick.
- Cannot spread TB germs to others.
- Usually has a positive TB blood test or TB skin test indicating TB infection.
- Has a normal chest x-ray and if performed, negative laboratory tests (for example, sputum smear or culture).
- Needs treatment for inactive TB to prevent active TB disease.
Symptoms
People with inactive TB do not have symptoms of TB disease. However, without treatment, they can develop active TB disease and become sick.
Talk to your health care provider if you have symptoms of TB disease.
Risk factors
Anyone can get infected with TB germs, but you might have a higher risk if you:
- Were born in or frequently travel to countries where TB is common, including those in Asia, Africa, and Latin America
- Live or used to live in large group settings where TB is more common, such as homeless shelters, prisons, or jails
- Recently spent time with someone who has active TB disease
- Work in places where TB is more likely to spread, such as hospitals, homeless shelters, correctional facilities, and nursing homes
You may be at risk for inactive TB even if you have received the TB vaccine (also called the BCG vaccine).
How it spreads
A person with inactive TB cannot spread TB germs to other people.
You do not need to be tested for TB if you've spent time with someone with inactive TB.
However, you should be tested for TB if you have spent time with someone with active TB disease or someone with symptoms of TB disease.
Prevention
If you have inactive TB, treating it is the best way to protect you from getting sick with active TB disease.
People who live or work in settings where TB may be more likely to spread, such as hospitals, homeless shelters, correctional facilities, and nursing homes, may be required to get tested for TB periodically.
Quick facts
- CDC estimates up to 13 million people in the United States live with inactive TB.
- Without treatment, 1 in 10 people with inactive TB will get sick with active TB disease. TB disease can spread to others and be deadly.
- If you have inactive TB, treating it is the best way to protect you from getting sick with active TB disease.
Did you know?
Testing and diagnosis
Testing
There are two types of tests for TB infection: the TB blood test and the TB skin test. Talk with your health care provider about which TB test is best for you.
TB Blood Test
TB blood tests (also called interferon-gamma release assay or IGRAs) use a blood sample to find out if you are infected with TB germs. The tests measure how your immune system reacts when a small amount of your blood is mixed with TB proteins.
Tell your health care provider if you received a TB vaccine
TB Skin Test
For the TB skin test, a health care provider uses a small needle to put some testing material under the skin. You will need to return to your health care provider in two to three days to see if there is a reaction.
Understanding TB Blood Test or TB Skin Test Results
A positive test result for TB infection means you have TB germs in your body. Your health care provider will do other tests to determine if you have inactive TB or active TB disease. These tests may include a chest x-ray, and a test of the sputum (phlegm) you cough up.
A negative test result for TB infection means you likely do not have inactive TB or active TB disease.
Diagnosis
If you have a positive TB blood test or TB skin test, but your health care provider does not find evidence of TB disease after a medical evaluation, you may be diagnosed with inactive TB.
Treatment
If you have inactive TB, short and convenient treatments are available that can help protect you from getting sick with active TB disease. You and your health care provider will decide which treatment is best for you.
If you take your medicine as instructed, it can keep you from developing TB disease. Because there are less TB germs, treatment for inactive TB is much easier than treatment for TB disease.