The TB Classification System

Tuberculosis findings in the immigration medical exam are classified using a system established by the CDC and USCIS Technical Instructions. The two primary classifications are Class A and Class B. Each has different implications for admissibility and post-admission obligations.

The classification is based on the results of TB screening (TST or IGRA), chest X-ray findings, and clinical evaluation. The civil surgeon applies the CDC Technical Instructions to determine the appropriate classification.

Class A Tuberculosis — Active TB, Inadmissible

A Class A tuberculosis designation means the applicant has active, infectious tuberculosis. Active TB is a communicable disease of public health significance under INA § 212(a)(1)(A)(i), which makes the applicant inadmissible.

Class A TB is not a permanent bar to admission. The applicant must complete treatment for active TB before they can be admitted. Once treatment is complete and the applicant is no longer infectious, the civil surgeon can update Form I-693 to reflect the change in status. A waiver under INA § 212(g)(1) may also be available in certain circumstances.

Attorneys with clients who receive a Class A TB designation should work with the civil surgeon to understand the treatment timeline and coordinate the re-examination after treatment is complete. Active TB treatment typically takes 6–9 months.

Class B Tuberculosis — Inactive TB, Admissible With Follow-Up

A Class B tuberculosis designation means the applicant has TB-related findings that do not indicate active, infectious disease. Class B applicants are admissible — the designation does not create a ground of inadmissibility. However, Class B applicants are required to follow up with a health department or physician after admission for evaluation and, if indicated, treatment of latent TB infection.

Class B designations are further divided into subcategories: Class B1 (pulmonary TB, not infectious), Class B2 (extrapulmonary TB), and Class B3 (latent TB infection with risk factors). Each subcategory has different follow-up requirements.

Class B Follow-Up Obligations

Applicants with a Class B TB designation are required to report to a health department or physician within 30–90 days of admission (the specific timeframe depends on the subcategory and state requirements). Failure to comply with follow-up requirements can have immigration consequences.

Attorneys should advise Class B clients of their follow-up obligations before admission. Provide the client with written instructions and contact information for the local health department. Document that the client received this information.

In most cases, Class B follow-up results in a finding of latent TB infection (LTBI), which is treated with a course of preventive therapy (typically isoniazid for 6–9 months or a shorter rifamycin-based regimen). LTBI treatment does not affect the client's immigration status.

The TB Testing Process

TB screening begins with either a tuberculin skin test (TST) or an interferon-gamma release assay (IGRA, such as QuantiFERON-TB Gold). A positive TST or IGRA triggers a chest X-ray. The chest X-ray findings, combined with the clinical evaluation, determine the classification.

TST requires a 48–72 hour return visit for the test to be read. IGRA is a blood test that can be processed in a laboratory without a return visit. The choice of test depends on the civil surgeon's clinical judgment and the applicant's history (prior BCG vaccination can cause false-positive TST results; IGRA is preferred for BCG-vaccinated applicants).

Attorneys should be aware that TB testing adds time to the exam process. If the applicant has a positive TST or IGRA, additional time is needed for the chest X-ray and clinical evaluation. Plan for a minimum of 3–5 business days for the complete TB evaluation.

Prior BCG Vaccination and TB Testing

Many applicants from countries where TB is endemic received BCG (Bacillus Calmette-Guérin) vaccination as children. BCG vaccination can cause a false-positive TST result. Attorneys should advise clients to disclose BCG vaccination history at the exam. The civil surgeon will typically use IGRA (rather than TST) for BCG-vaccinated applicants to avoid false positives.

Attorney Checklist for TB Cases

For clients from high-TB-burden countries or with known TB exposure history, attorneys should: (1) advise the client to disclose TB history and BCG vaccination status at the exam, (2) plan for a longer exam timeline (3–5 business days minimum), (3) if a Class B designation is received, document the follow-up obligations and provide the client with written instructions, and (4) if a Class A designation is received, work with the civil surgeon to understand the treatment timeline and coordinate the re-examination.