Tuberculosis (TB) is an infectious disease caused by bacteria that most often affects the lungs. It spreads through the air when an infected person coughs or sneezes. While TB primarily impacts the lungs, it can also affect other parts of the body, such as the kidneys, spine, or brain. Not everyone infected with TB bacteria becomes sick, but testing helps identify those who carry the bacteria. Testing for TB is an important step in managing this global health concern.
Where to Get Tested
Accessing TB testing is possible through several common healthcare avenues. Public health departments and clinics frequently offer TB testing services, often at reduced costs or even for free. Private doctor’s offices and general clinics also provide TB testing, offering convenience for individuals with an established healthcare provider. Urgent care centers represent another convenient choice for immediate TB testing needs, as they offer walk-in appointments without prior scheduling.
Additionally, some workplaces and educational institutions may offer TB screening programs, especially for individuals in professions or settings with a higher risk of exposure. Healthcare workers, for instance, often undergo regular TB testing as part of their employment requirements.
What to Expect During a TB Test
Two primary types of tests are used to detect TB infection: the Tuberculin Skin Test (TST) and blood tests known as Interferon-Gamma Release Assays (IGRAs). The TST, also called a PPD test, involves a healthcare provider injecting a small amount of fluid called tuberculin into the skin of your forearm. You must return to the clinic within 48 to 72 hours for a healthcare professional to examine the injection site. A reaction, such as a firm swelling, indicates a positive result, suggesting TB infection.
Blood tests, or IGRAs, are a different approach, requiring a single visit to draw a blood sample. Common IGRA tests include the QuantiFERON-TB Gold and T-SPOT.TB. These tests measure the immune system’s reaction to TB bacteria in the blood. If either test yields a positive result, it requires further evaluation, such as a chest X-ray, to determine if it is a latent infection or active disease.
Why TB Testing is Important
TB testing plays an important role in both individual health and broader public health efforts. Identifying a latent TB infection (LTBI) is important because it allows for preventive treatment to begin, stopping the infection from progressing to active TB disease. Individuals with latent TB do not have symptoms and are not contagious, but they can develop active disease later.
Screening for TB is also often a requirement for specific situations, such as certain types of employment, immigration processes, school enrollment, or travel to areas where TB is more common. By detecting and treating TB infections early, testing helps protect individuals and contributes to reducing the overall burden of TB in the population.