The 2026 Guide to Immigration TB Testing: IGRA Blood Tests vs. Skin Tests

When applying for a green card through adjustment of status, a critical step of your USCIS medical exam (Form I-693) is the tuberculosis (TB) screening. For many applicants, understanding the medical requirements can be confusing—especially the difference between a traditional skin test and the required blood test.

If you are completing your exam in the greater Indianapolis or Northwest Indiana region, understanding this requirement ensures your paperwork is processed without delays.

1. What Are the Two Types of TB Tests?

To detect a tuberculosis infection, clinics generally use one of two methods:

• The Tuberculin Skin Test (TST): Historically known as the Mantoux test, this method involves injecting a small amount of fluid (tuberculin) under the skin of the forearm. You must return to the clinic 48 to 72 hours later to have a healthcare provider inspect and measure the reaction.
• The Interferon Gamma Release Assay (IGRA): This is a modern, simple blood test (such as the QuantiFERON-TB Gold or T-SPOT.TB test). It measures how your immune system responds to TB bacteria from a single blood draw.

2. Why USCIS Requires the Blood Test (IGRA)

Under current CDC and USCIS guidelines, the IGRA blood test is the preferred and required method for most immigration medical exams involving applicants two years of age or older.

The blood test offers distinct advantages over the skin test:

• Convenience: The blood test requires only one visit to the office. The skin test requires you to return within 48 to 72 hours for a second check.
• Accuracy: Skin tests can occasionally trigger false-positive results if you have received the BCG vaccine in the past, which is common for applicants from many countries outside the U.S.
• Reliability: The blood test is unaffected by prior vaccinations, minimizing the chance of an incorrect reading.

3. What Do Your Results Mean?

After the sample is processed by the lab, your results will fall into one of two categories:

A. Negative Results

If your IGRA test comes back negative, you are clear of the infection. Your Civil Surgeon will record the result on your Form I-693, and you can proceed with the rest of your application.

B. Positive Results

If your result is positive, it means your immune system has been exposed to the TB bacteria. This does not mean you are disqualified from your green card. However, it does mean you require further medical evaluation to ensure you do not have active tuberculosis disease.

If your test is positive, the standard protocol includes:

1. A Chest X-ray: To evaluate your lungs and rule out active disease.
2. Clinical Evaluation: A Civil Surgeon will review your chest X-ray and medical history.

4. The 1Smile Dental & Lab On Demand Connection

At 1Smile Dental, we understand that navigating the medical and diagnostic requirements of the immigration process can feel overwhelming. That is why we coordinate with physician-led diagnostic networks such as Lab On Demand to provide fully managed, integrated lab panels and USCIS-compliant I-693 processing for applicants throughout Indiana and the greater Midwest.

👉 Read more about our integrated clinical partnerships in our https://labondemandind.com/navigating-immigration-vaccines-for-your-i-693/

Frequently Asked Questions (FAQ)

Does a positive TB blood test mean I cannot get a green card?

No. A positive result simply means you have been exposed. Provided a chest X-ray shows no active disease, you can still meet the health requirements for adjustment of status.

Can children under 2 take the blood test?

Children under the age of 2 are generally exempt from the testing requirement, unless they have been in direct contact with an individual known to have active tuberculosis.

How long are the test results valid for the I-693 form?

Under current guidelines, the entire medical report generally remains valid for up to two years before you submit it to USCIS.

Get fast, accurate IGRA testing with one visit and seamless coordination with your Civil Surgeon—no delays, no repeat visits.

Lab On Demand proudly serves Greenwood, Indianapolis, Carmel, Fishers, Westfield, Zionsville, Noblesville, and surrounding areas, offering efficient, patient-focused lab testing for both preventive health and immigration medical exams.