Do I Need a TB Test? What Happens If I Test Positive for TB?
TB test often required for work, school and volunteering
TB test often required for work, school and volunteering
Tuberculosis is a serious disease that affects people around the world. While it is less common in the United States, tuberculosis or TB is still a major health concern because it spreads easily and is contagious.
TB is a bacterial infection that spreads through the air when someone with an active infection coughs or speaks. It usually affects the lungs but can also affect other parts of the body, including the kidneys, spine and brain. It’s usually treated via a four- to nine-month course of multiple antibiotics.
The bacteria that cause TB can stay in the body for years without showing symptoms.
“In some cases, the immune system fights the infection. Instead of becoming sick with TB, these people have what is known as latent TB infection,” says Zhaoyi Qin, MD, an internal medicine physician at Scripps Clinic Torrey Pines. “This means they have the bacteria in their bodies, but do not have active TB.”
People with inactive TB don’t feel sick, nor can they spread the disease to others. But, if their latent TB is not treated, it may develop into active TB, which is contagious. This can happen without warning, so it is important to get tested for TB and learn if you may be at risk of infecting others.
Who should get tested?
You may need a TB test, if you:
- Have symptoms like a persistent cough, chest pain, coughing up blood or phlegm
- Have been near someone with TB
- Have a weakened immune system because of medication or health problems
- Live or have lived in crowded places like homeless shelters, prisons or jails
- Inject illegal drugs
- Were born in or visit countries where TB is common
In addition, you may need a TB test to participate in certain activities.
“Testing is recommended, if not required, before starting a new job, transferring to a different school or volunteering,” says Dr. Qin. “Testing is especially important in schools, health care environments and other places where the risk of TB is increased because of close contact between people who may be ill or have weak immune systems.”
What is a TB test and how is it done?
Two types of tests are used to detect TB in the body:
TB skin test
The TB skin test involves injecting a small amount of fluid under the skin of your forearm. Within two or three days, a health care provider checks the injection site for any swelling or bumps, which can indicate TB infection.
Tell your provider if you have had a TB vaccine because the vaccine may cause a skin test to show a false positive result. TB blood tests are not affected by the vaccine.
The TB vaccine is not widely used in the U.S. However, it is commonly given to infants and small children in countries where TB is more common.
TB blood test
A blood test can detect TB bacteria. The test measures how the immune system reacts when a small amount of blood is mixed with TB proteins. It only requires one visit to a health care provider.
What happens if my TB test is positive?
A positive TB test result means only that TB bacteria has been detected. It does not indicate whether the person has active or inactive TB. That requires additional testing, including a chest X-ray.
If you have active TB, you will need to take medicine to treat the disease.
About 13 million people in the U.S. have inactive or latent TB. If left untreated, 1 out of 10 people with inactive TB will develop active TB, according to the Centers for Disease Control and Prevention.
If you have inactive TB, your physician will determine if you need treatment after weighing the benefits versus the risks. Treatment for inactive TB can last for three to nine months, depending on the treatment plan. Different medicines may be used together.
Where can I get a TB test?
TB testing is available at Scripps HealthExpress convenient walk-in clinics located at Scripps Clinic and Scripps Coastal Medical Center locations throughout San Diego County, as well as at your Scripps primary care physician’s office.