Tuberculosis classification system
The current clinical classification system for tuberculosis (TB) is based on the pathogenesis of the disease.1
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.2
Classification System for TB| Class | Type | Description |
|---|---|---|
| 0 | No TB exposureNot infected | No history of exposureNegative reaction to tuberculin skin test |
| 1 | TB exposureNo evidence of infection | History of exposureNegative reaction to tuberculin skin test |
| 2 | TB infection No disease | Positive reaction to tuberculin skin testNegative 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 pendingTB 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).3 The B notification program is an important screening strategy to identify new arrivals who have a high risk for TB.4
United States Immigrant/Refugee TB Classification - revised 2009| Class |
|---|
| No TB Classification (Normal) |
| Class A TB with waiver, infectious |
| Class B1 TB, Pulmonary |
| Class B1 TB, Extrapulmonary |
| Class B2 TB Latent TB Infection (LTBI) Evaluation |
| Class B3 TB, Contact Evaluation |
See also
- list of notifiable diseases
- Tuberculosis radiology for CXR details
- Tuberculosis diagnosis
References
"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. 161 (4): 1376–1395. 1 April 2000. doi:10.1164/ajrccm.161.4.16141. PMID 10764337. Class 0-5 are explained on pages 1391-1392 https://doi.org/10.1164%2Fajrccm.161.4.16141 ↩
"Menu of Suggested Provisions For State Tuberculosis Prevention and Control Laws". Centers for Disease Control and Prevention. A. Mandated Reporting: 1. Required Reporters of Communicable Disease https://www.cdc.gov/tb/programs/laws/menu/caseid.htm ↩
CDC Immigration Requirements: Technical Instructions for Tuberculosis Screening and Treatment. October 1, 2009. Classifications, see pages 21-22. https://www.cdc.gov/immigrantrefugeehealth/pdf/tuberculosis-ti-2009.pdf ↩
Revised CDC TB Classification system for overseas screening of immigrants and Refugees with Class B1/B2 TB Conditions Archived 2011-07-08 at the Wayback Machine. 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. http://www.dhs.wisconsin.gov/tb/pdf/Letter%20B1_B2%20FINAL_10_09.pdf ↩