Table.

TB Classifications Used by the Smear- and Culture-Based Algorithms

TB Classification	Smear-Based Algorithm	Culture-Based Algorithm
Class A	≥1 sputum smear results were positive. Persons diagnosed with class A TB had to complete TB treatment overseas and would be reclassified as having class B2 TB.	≥1 sputum smear or culture results were positive or TB was clinically diagnosed. Persons diagnosed with class A TB had to complete directly observed therapy for TB overseas and would be reclassified as having class B1 TB.
	Class A TB waiver: Persons with class A TB received TB treatment overseas until their sputum smear results became negative and applied for an immigration waiver. A class A TB waiver is rare. Follow-up evaluation after arrival in the United States is mandated for persons with a class A TB waiver.	Class A TB waiver: Persons with class A TB received directly observed therapy until their sputum smear and culture results became negative and applied for an immigration waiver. A class A TB waiver is rare. Follow-up evaluation after arrival in the United States is mandated for persons with a class A TB waiver.
Class B1	Chest radiograph suggestive of active TB	Chest radiograph, medical history, or examination suggestive of TB
Class B2	Chest radiograph suggestive of inactive TB	NA
Class B2 latent TB infection	NA	Induration of ≥ 10 mm on TST or positive results on an IGRA
No TB	Normal chest radiograph	Normal chest radiograph

IGRA = interferon-γ release assay; NA = not applicable; TB = tuberculosis; TST = tuberculin skin test.