Latent TB Infection: What It Means

Latent TB infection (LTBI) occurs when TB bacteria enter the body and the immune system contains them, preventing active disease. The bacteria remain alive but dormant — like seeds that have not yet germinated. People with latent TB infection have no symptoms, are not contagious, and typically feel completely healthy.

Latent TB infection is detected through a positive TB blood test (IGRA) in the absence of symptoms and with a normal chest X-ray. It is estimated that approximately one-quarter of the world's population has latent TB infection, making it extremely common among immigration applicants from high-TB-burden countries.

Active TB Disease: What It Means

Active TB disease occurs when the TB bacteria overcome the immune system's containment and begin to multiply, causing illness. Active TB most commonly affects the lungs (pulmonary TB) but can affect other parts of the body (extrapulmonary TB). People with active pulmonary TB can spread the disease to others through the air when they cough, sneeze, or speak.

Symptoms of active TB disease include a persistent cough lasting more than 3 weeks, coughing up blood or sputum, chest pain, fever, night sweats, fatigue, and unexplained weight loss. Active TB disease requires prompt medical treatment.

Immigration Implications of Latent TB

Latent TB infection is generally not a ground of inadmissibility under U.S. immigration law. If your IGRA blood test is positive but your chest X-ray is normal and you have no symptoms of active TB disease, the civil surgeon will document latent TB infection on Form I-693. Your immigration application can typically proceed.

USCIS may note the latent TB finding in your file and recommend that you follow up with a healthcare provider after obtaining your green card to discuss whether treatment for latent TB is appropriate. Treatment for latent TB (typically a short course of antibiotics) reduces the risk of the infection progressing to active disease in the future.

Immigration Implications of Active TB Disease

Active TB disease is a communicable disease of public health significance and is a ground of inadmissibility under the Immigration and Nationality Act. If active TB disease is identified during your immigration medical exam, your Form I-693 cannot be finalized until treatment is completed.

Treatment for active TB typically involves a combination of antibiotics taken for 6 to 9 months. Once treatment is successfully completed and you are no longer infectious, your civil surgeon can complete Form I-693 and your immigration case can move forward. Documentation of completed treatment is essential.

How the Civil Surgeon Distinguishes Between Latent and Active TB

The civil surgeon uses a combination of findings to determine whether you have latent TB infection or active TB disease:

• IGRA blood test result (positive or negative)
• Chest X-ray findings (normal vs. abnormal)
• Presence or absence of TB symptoms
• Physical examination findings
• TB history and prior treatment records
• Sputum testing if active disease is suspected