Table 1.

Differentiating Active Tuberculosis Disease and Latent Tuberculosis Infection

Feature	Active TB Disease	Latent TB Infection
Signs and symptoms	May include one or more:  Chest pain  Cough  Decreased appetite  Fatigue  Fever  Hemoptysis  Night sweats  Weight loss	None
IGRA or TST	Usually positive; negative test result does not rule out active TB	Usually positive
Chest radiograph	Usually abnormal*	Usually normal
Respiratory specimens	Usually smear- or culture-positive†	Smear- and culture-negative‡
Infectious	Yes	No

TB, tuberculosis; IGRA, interferon-gamma release assay; TST, Mantoux tuberculin skin test.

Data from Centers for Disease Control and Prevention. Latent TB Infection and TB Disease. Available at: https://www.cdc.gov/tb/topic/basics/tbinfectiondisease.htm. Retrieved February 17, 2020.

^*Chest radiograph may be normal in persons with advanced immunosuppression or extrapulmonary disease.

^†Respiratory specimen smears or cultures may be negative in persons with extrapulmonary disease or minimal or early pulmonary disease.

^‡Respiratory specimens are obtained only if ruling out active TB disease based on abnormal chest radiograph, symptoms, or clinical suspicion.