Tuberculosis classification

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title: "Tuberculosis classification" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["tuberculosis", "medical-classification"] description: "Classification system for tuberculosis" topic_path: "general/tuberculosis" source: "https://en.wikipedia.org/wiki/Tuberculosis_classification" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Classification system for tuberculosis ::

Main article: Tuberculosis

Tuberculosis classification system (US)

As of April 2000, the American clinical classification system for tuberculosis (TB) is based on the pathogenesis of the disease.

Health care providers should comply with local laws and regulations requiring the reporting of TB. All persons with class 3 or class 5 TB should be reported promptly to the local health department.

::data[format=table title="Classification System for TB"]

Class	Type	Description
0	No TB exposure
Not infected	No history of exposure
Negative reaction to tuberculin skin test
1	TB exposure
No evidence of infection	History of exposure
Negative reaction to tuberculin skin test
2	TB infection
No disease	Positive reaction to tuberculin skin test
Negative bacteriologic studies (if done)
No clinical, bacteriologic, or radiographic evidence of TB
3	TB, clinically active	M. tuberculosis cultured (if done)
Clinical, bacteriologic, or radiographic evidence of current disease
4	TB
Not clinically active	History of episode(s) of TB
or
Abnormal but stable radiographic findings
Positive reaction to the tuberculin skin test
Negative bacteriologic studies (if done)
and
No clinical or radiographic evidence of current disease
5	TB suspect	Diagnosis pending
TB disease should be ruled in or out within 3 months
::

CDC TB classification for immigrants and refugees

The U.S. Citizenship and Immigration Services has an additional TB classification for immigrants and refugees developed by the Centers for Disease Control and Prevention (CDC).CDC Immigration Requirements: Technical Instructions for Tuberculosis Screening and Treatment. October 1, 2009. Classifications, see pages 21-22. The B notification program is an important screening strategy to identify new arrivals who have a high risk for TB. ::data[format=table title="United States Immigrant/Refugee TB Classification - revised 2009"]

Class	Description	None	A	B1	B2	B3
No TB Classification (Normal)
TB with positive sputum smear (considered infectious; requires a waiver to enter US)
Overseas evidence of TB with negative sputum smear (considered non-infectious; includes pulmonary and extrapulmonary); includes "old healed TB" and previously treated TB
Latent TB Infection (LTBI) defined as tuberculin skin test ≥ 10 mm
TB contact
::

References

References

1. (1 April 2000). "Diagnostic Standards and Classification of Tuberculosis in Adults and Children: This Official Statement of the American Thoracic Society and the Centers for Disease Control and Prevention was Adopted by the ATS Board of Directors, July 1999. This Statement was endorsed by the Council of the Infectious Disease Society of America, September 1999". American Journal of Respiratory and Critical Care Medicine.
2. (2010). "Menu of Suggested Provisions For State Tuberculosis Prevention and Control Laws".
3. [http://www.dhs.wisconsin.gov/tb/pdf/Letter%20B1_B2%20FINAL_10_09.pdf Revised CDC TB Classification system for overseas screening of immigrants and Refugees with Class B1/B2 TB Conditions] {{Webarchive. link. (2011-07-08 . State of Wisconsin, Department of Health Services, Division of Public Health, International Health and Respiratory Disease Unit, Bureau of Communicable Diseases and Emergency Response. September 29, 2009. Accessed 2011-07-27.)

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