How would someone know if they have TB? They Get Tested.
Because TB bacteria is spread through the air, it is difficult to prevent acquiring either latent TB infection or TB disease. Anyone who has symptoms of TB, or thinks they may have been exposed to someone with TB disease, should be tested.
People who could benefit from TB testing include:
- people who have spent time with a person known or suspected to have TB disease.
- people with HIV infection or another condition that weakens the immune system.
- people who have symptoms of TB disease (fever, cough lasting more than 3 weeks, night sweats, coughing up blood).
- people who are from or spent a considerable amount of time in countries where TB is common.
- people who live in congregate settings (i.e. homeless shelters, jails, some nursing homes, etc.).
- people who inject illegal drugs.
Testing for TB Infection
There are a number of steps needed to determine if someone has TB infection or TB disease. The first step is to have either a TB skin test (TST) or TB blood test to determine if a person is infected with the TB bacteria. A TST is when a health care worker injects a small amount of fluid under the skin on the forearm. The fluid will react with a person's immune system and will grow into a raised bump if reactive. To receive a result, the test must be assessed by a healthcare worker within 48-72 hours. TSTs should not be used with people who have had the TB vaccine (BCG) as it will likely result in a reactive result even if the person is not infected.
The TB blood test, which is also called an Interferon Gamma Release Assay (IGRA), tests to determine if the bacteria that cause TB infection or TB disease are within a person. These tests are best for people who have a history of TB vaccination (BCG) because this test will not return a false positive in these instances. People who are unable to have a test result read by a healthcare provider within 48-72 hours may also benefit from an IGRA test as someone doesn't have to have results read.
People who are tested for TB infection and have negative tests results likely aren't infected with TB. However, when someone has symptoms of TB disease and a condition that weakens the immune system, this initial test could show a false negative. These people are recommended to continue on with testing by chest x-ray or CT and to submit sputum specimens to ensure the initial test wasn't a false negative.
For people who were tested because they were exposed to someone with TB disease will likely be recommended to be screened initially, and then at least 8-10 weeks after the last time they spent time with the person with TB disease. If both tests are negative, it is unlikely that person's exposure caused them to be infected with TB.
For people whose TB Infection tests are positive, additional testing for TB Disease is necessary.
Testing for TB Disease
When a TST or blood test is positive, this means that a person likely is infected with TB bacteria. Further testing to determine if a person has TB infection or TB disease. A healthcare provider will perform a chest x-ray or CT scan to look at a persons lungs and will submit a sputum sample to look for the TB bacteria in the laboratory. If there is no evidence of TB disease in an chest x-ray or CT scan, no TB bacteria present in sputum and/or no symptoms present of TB disease, a healthcare provider will likely determine that a person only has TB infection.
If the chest x-ray or CT scan show signs of TB disease and/or the sputum shows TB bacteria, a healthcare provider will likely determine a person has TB disease.
Testing for TB infection and TB disease available at your primary care provider or some local public health units.
How would someone be cured from TB Infection or TB Disease? They Get Treatment.
Both TB infection and TB disease should be treated with antibiotics for a duration as prescribed by a healthcare provider. Treating TB infection is the best preventative tool available to prevent TB disease.
Treatment for TB Infection
There are currently four regimens that could be chosen by a healthcare provider to treat TB infection. These regimens are all effective and the regimen will best suit the patient will be chosen by the healthcare provider. These regimens include:
- Isoniazid (INH) for 6 months Isoniazid-specific Regimen Fact Sheet
- Isoniazid (INH) for 9 months
- Rifampin (RIF) for 4 months Rifampin-specific Regimen Fact Sheet
- Isoniazid (INH) and Rifapentine (RPT) for 3 months Isoniazid and Rifapentine-specific Regimen Fact Sheet
Treatment bay be modified if the person was determined to be a contact to a person who has been diagnosed with multi-drug resistant TB disease.
Treatment for TB Disease
When someone is diagnosed with TB disease, it is essential they start antibiotic therapy and finish the regimen exactly as prescribe. If treatment is stopped too early, it's possible people will become sick again, and possibly the TB bacteria that remain will then be resistant to antibiotics. TB bacteria that are resistant to antibiotics are harder to treat.
Standard TB disease regimens generally include:
- isoniazid (INH)
- rifampin (RIF)
- ethambutol (EMB)
- pyrazinamide (PZA)
Regimens for treating TB disease have an intensive phase for two months, followed by a continuation phase for an additional 4-7 months. Alternative regimens may be prescribed based on a person's medical history, other co-morbid conditions and/or based on local epidemiology of tuberculosis as determined by a healthcare provider.
Side Effects of Antibiotics Used to Treat TB
As with many medicines, the antibiotics used to treat TB infection and TB disease can cause side effects. If a person is taking treatment for TB infection or TB disease and experience any of the following side effects, they should talk to their doctors immediately.
Protection from TB Infection and TB Disease
Preventing Exposure to TB Disease While Traveling Abroad
TB is much more common in countries outside of the United States. Those who travel to areas of sub-Saharan Africa, Asia and parts of Central and South America are at greatest risk. Travelers who anticipate possible prolonged exposure to individuals with TB (e.g. those who routinely spend time in clinics, hospitals, prisons or homeless shelters) should have a TB skin test or a TB blood test before leaving the United States. If the test reaction is negative, they should have a repeat test in 8 to 10 weeks after returning to the United States.
Bacille Calmette-Guérin (BCG) is a vaccine for tuberculosis (TB) disease. This vaccine is not widely used in the United States, but it is often given to infants and small children in other countries where TB is common. Unfortunately, BCG is only partially effective. It provides some protection against severe forms of pediatric TB, but is not completely protective against disease in infants and is unreliable against adult pulmonary TB. BCG does not always protect people from getting TB.
In the United States, BCG should be considered for only select individuals who consult with a TB expert and meet specific criteria. Health care providers who consider BCG vaccination for their patients are encouraged to discuss this intervention with the TB Control Program.