Why TB Testing Is Required for Immigration

Tuberculosis (TB) is a communicable disease of public health significance and is one of the specific medical grounds of inadmissibility under U.S. immigration law. Because of this, TB screening is a mandatory component of the immigration medical exam for all applicants, regardless of age or country of origin.

TB screening for immigration purposes involves two components: a TB test (either a skin test or a blood test) and a chest X-ray. Both are required for applicants age 15 and older. The combination of these two tests allows the civil surgeon to identify both latent TB infection (LTBI) and active TB disease.

TST vs. IGRA: Which Test Is Used for Seniors

There are two types of TB tests used in immigration medical exams: the tuberculin skin test (TST), also known as the Mantoux test or PPD test, and the interferon-gamma release assay (IGRA), which is a blood test. The most common IGRA tests are QuantiFERON-TB Gold Plus and T-SPOT.TB.

Both tests are acceptable for immigration purposes. The civil surgeon has discretion to use either test, and many clinics use IGRA as the preferred method for all adult applicants. For seniors specifically, IGRA is often the better choice for two important reasons: first, many seniors from other countries received the BCG (Bacille Calmette-Guérin) vaccine in childhood, which can cause a false-positive TST result; second, seniors who are on immunosuppressive medications may have a blunted immune response that makes the TST less reliable.

IGRA blood tests are not affected by prior BCG vaccination and are generally more specific than the TST. They require only a single blood draw and do not require a return visit for reading, unlike the TST which must be read 48–72 hours after placement. For seniors who may have difficulty making multiple trips to the clinic, IGRA offers a practical advantage.

BCG Vaccination History in Seniors

Many seniors who grew up outside the United States received the BCG vaccine as children or young adults. BCG is widely used in countries with high TB prevalence to protect against severe forms of TB in children. However, BCG vaccination can cause a positive TST result for years or even decades after vaccination, making it difficult to distinguish between a BCG-related reaction and a true TB infection.

If you received BCG as a child, inform the civil surgeon at your appointment. This history is important for interpreting your TB test results. If a TST is used and the result is positive, the civil surgeon will take your BCG history into account. In many cases, an IGRA blood test will be ordered to clarify the result, since IGRA is not affected by BCG vaccination.

It is worth noting that BCG vaccination received in adulthood (rather than infancy) is more likely to cause a persistent positive TST. If you received BCG as an adult — for example, as a healthcare worker — be sure to mention this as well.

Seniors on Immunosuppressive Medications

Seniors who are taking immunosuppressive medications — such as corticosteroids, methotrexate, biologics (TNF inhibitors), or medications used after organ transplant — may have a reduced immune response that affects the accuracy of TB testing. Both the TST and IGRA rely on the immune system's response to TB antigens, so immunosuppression can lead to false-negative results.

For seniors on immunosuppressive therapy, the civil surgeon will take your medication history into account when interpreting TB test results. In some cases, the civil surgeon may rely more heavily on the chest X-ray findings or may consult with your treating physician. If you are on immunosuppressive medications, bring a complete list of your medications and dosages to your appointment.

It is important not to stop immunosuppressive medications before your immigration medical exam without consulting your treating physician. Stopping these medications can have serious health consequences and is not required for the immigration exam.

What a Positive TB Test Result Means

A positive TB test result — whether TST or IGRA — indicates that you have been exposed to TB bacteria at some point in your life. It does not necessarily mean you have active TB disease. Most people with a positive TB test have latent TB infection (LTBI), meaning the bacteria are present in the body but are not causing illness and are not contagious.

If your TB test is positive, the civil surgeon will review your chest X-ray findings and may ask additional questions about your symptoms and medical history. If the chest X-ray is normal and you have no symptoms of active TB, a diagnosis of latent TB infection is likely. Latent TB is not a ground of inadmissibility and does not prevent you from obtaining a green card.

If the chest X-ray shows findings consistent with active TB, or if you have symptoms such as persistent cough, night sweats, or unexplained weight loss, the civil surgeon will refer you for further evaluation. Active TB disease is a ground of inadmissibility, but it can be treated, and inadmissibility can be resolved once treatment is complete and you are no longer infectious.

The Follow-Up Process After a Positive Result

If you are found to have latent TB infection, you may be referred to a public health department or infectious disease specialist for evaluation and possible treatment. Treatment of latent TB is not required for immigration purposes, but it is recommended by public health authorities to prevent the development of active TB disease in the future.

If active TB is suspected or confirmed, you will be referred for a full diagnostic workup and treatment. The civil surgeon cannot complete Form I-693 until active TB has been treated and you have been cleared by the appropriate medical authority. This process can take several months, but it does not permanently bar you from immigration — it simply delays the completion of your medical exam until the condition is resolved.