TB Testing is recommended for individuals who are at a higher risk of Tuberculosis Infection or have been exposed to someone with active TB. This includes health-care workers, individuals living or working in congregate settings such as nursing homes, prisons, or homeless shelters, and people with weakened immune systems, such as those with HIV/AIDS or receiving immunosuppressive therapy. TB testing is also important for individuals who have traveled to or lived in countries with high TB prevalence. The two main Types of TB tests are the Tuberculin Skin Test (TST) and the TB Blood Test (interferon-gamma release assays or IGRA). The TST involves injecting a small amount of tuberculin purified protein derivative (PPD) under the skin and measuring the reaction after 48-72 hours. The IGRA is a blood test that measures the immune response to TB bacteria. Positive results from either test indicate TB infection, but additional tests such as a chest X-ray and sputum sample are needed to determine if the infection is latent or active.