TB Screening for USCIS, Explained

Tuberculosis screening is mandatory for every applicant aged 2 and older going through the I-693 medical exam. It is the single most common cause of immigration delays related to the medical — about 6% of applicants screen positive, and how the Civil Surgeon handles the follow-up flow determines whether your case stalls for weeks or moves forward in five business days.

What changed in October 2018

Before October 1, 2018, the Centers for Disease Control and Prevention (CDC) Technical Instructions allowed Civil Surgeons to use either the Mantoux Tuberculin Skin Test (TST), commonly called the PPD, or an Interferon Gamma Release Assay (IGRA) blood test. The skin test had a high false-positive rate — particularly in applicants from countries that vaccinate with BCG (Bacillus Calmette-Guérin) in childhood, which is the vast majority of the world outside the U.S.

As of October 1, 2018, the CDC mandated IGRA only for applicants aged 2 and older. The TST is no longer an acceptable initial test for USCIS purposes. If a clinic still uses TST/PPD for adult immigrants, they are out of compliance with current Technical Instructions, and any I-693 they submit based on a TST result will be rejected.

IGRA: the technical detail

Two FDA-cleared IGRA tests are accepted:

Both tests are unaffected by prior BCG vaccination, which is the entire reason CDC moved to IGRA. Approximately 94% of applicants test negative on the first draw and move on without further evaluation.

If you test positive

A positive IGRA means you have been exposed to Mycobacterium tuberculosis at some point in your life. It does NOT automatically mean you have active disease — the vast majority of positives are latent TB infection (LTBI), where the bacterium is present but dormant and you are not contagious.

The USCIS flow after a positive IGRA is fixed:

1. Chest X-ray (PA view). The Civil Surgeon orders this immediately, typically same-day or next-day. The radiologist reads it for any sign of active pulmonary TB (cavitation, infiltrates, lymphadenopathy).
2. If chest X-ray is clear: You are classified as having LTBI, designated Class B latent TB, and are admissible. You receive a referral for treatment but treatment is not required for admission. Civil Surgeon completes the I-693 with the Class B designation and seals the envelope.
3. If chest X-ray is suspicious: Three sputum samples are collected over consecutive mornings and sent for AFB smear, culture, and nucleic acid amplification testing. This step takes 6–8 weeks for culture results.
4. If sputum confirms active TB: You are classified Class A and are inadmissible until treatment is complete (typically 6–9 months of multi-drug therapy under directly observed therapy, DOT). After successful treatment with documented cure, the Class A waiver/clearance allows the I-693 to proceed.

LTBI treatment options

Although treatment is not required for admission with a Class B LTBI designation, the CDC and most health departments strongly recommend it. Modern regimens are dramatically shorter than the older 9-month isoniazid (INH) course:

• 3HP (12-week regimen): Isoniazid plus rifapentine, once weekly for 12 weeks under DOT. Currently the preferred regimen for most LTBI patients.
• 4R (4-month regimen): Rifampin daily for 4 months. Self-administered; well tolerated.
• 3HR (3-month regimen): Isoniazid plus rifampin daily for 3 months. Good option when shorter is preferred.
• 6H or 9H (legacy): Daily isoniazid for 6 or 9 months. Still used in some cases (pregnancy, drug interaction concerns), but no longer first-line.

Class A vs. Class B inadmissibility

Under INA §212(a)(1)(A)(i), tuberculosis (active form) is a Class A communicable disease of public-health significance and is a ground of inadmissibility. Latent TB is not a ground of inadmissibility — it is recorded as Class B (a non-disqualifying health condition the U.S. medical system should follow up on after admission).

If you receive a Class A determination, you are not permanently barred. You complete treatment, the Civil Surgeon documents the cure, and you re-submit the I-693. A waiver under INA §212(g) is also available for some situations.

Pregnancy considerations

IGRA is safe in pregnancy — it is just a blood draw. If your IGRA is positive and a chest X-ray is needed, the radiology tech will provide lead shielding and the radiation dose to the fetus is negligible. Active TB during pregnancy is a serious condition and treatment cannot be safely deferred; rifampin and isoniazid are both well-studied in pregnancy. LTBI treatment is typically deferred until after delivery if there are no risk factors for progression.

Children under 2

Applicants under 2 do not receive IGRA testing. They are evaluated for TB risk factors by history and physical, and only undergo IGRA or chest X-ray if symptoms or risk factors warrant. This is intentional — IGRA performance is poor in very young children.

The fastest way to clear TB screening is to start with a Civil Surgeon who draws IGRA in-house and has a same-day chest X-ray referral pathway in case of a positive result. See our TB screening service page for what’s included at network clinics, or read the full I-693 complete guide for context on how the medical exam fits into your overall AOS timeline.