Tuberculosis, Latent (LTBI)



  • Latent tuberculosis infection (LTBI) is an asymptomatic, noninfectious condition following exposure to an active case of tuberculosis (TB). LTBI is usually detected by a screening skin/blood test.
  • Active TB occurs in 5–10% of infected individuals who have not received preventive therapy. Chance of active TB increases with immunosuppression and is highest for all individuals within 2 years of infection; 85% of the cases are pulmonary, which can be spread person-to-person via aerosol route.
  • >80% of active TB cases in the United States result from untreated LTBI.
  • LTBI treatment is a key component of the TB elimination strategy for the United States.
  • Nitrosamine particles have been isolated in rifampin (RIF) and rifapentine products in 2020 and through 2022. These nitrosamine particles are potential or probable carcinogens, and due to the life-threatening nature of TB, the FDA has approved ongoing production of these antimicrobials with close monitoring (1).
  • The current pace of decline in TB incidence will not eliminate TB in the United States in the 21st century. Extra effort is needed to identify patients with LTBI (2).


  • Epidemiology is difficult to assess because LTBI is not a reportable infection in many states.
  • In the United States, high-risk groups include immigrants from countries with a high TB rate (countries other than Canada, Australia, New Zealand, or a country in western or northern Europe); persons with a history of drug use or experiencing homelessness; HIV-infected or immunocompromised individuals; and persons living or working in high-risk congregate settings such as nursing homes, carceral facilities, and health care facilities (2).
  • Newly exposed (particularly children) are also at high risk.
  • On average, 5–10% of those infected with LTBI will go on to develop active TB in their lives, typically within 5 years (1).
  • In 2022, there were 8,300 TB cases reported in the United States.
  • The highest TB incidence for U.S.-born persons occurred among people of non-Hispanic white race/ethnicity, and the most likely medical diagnostic risk factor was a diagnosis of diabetes.

There are no estimates for annual incidence of LTBI in the United States.


  • Globally, ~2 billion people are estimated to be infected with TB. Globally, ~10 million people were diagnosed with active TB in 2020, of which ~1.1 million were children.
  • The CDC estimates 13 million people with LTBI (3).

Etiology and Pathophysiology

Mycobacterium tuberculosis, Mycobacterium bovis, and Mycobacterium africanum

Risk Factors

Immigrants from TB-endemic countries, which include most countries of Africa, Asia, and Eastern Europe; close contact with infected individual; living or working in a congregate setting (e.g., prison, nursing home); use of illicit drugs; lower socioeconomic status or experiencing homelessness; health care workers; laboratory personnel working with mycobacteria

General Prevention

  • Screen for LTBI and treat individuals with positive tests.
  • If a person has fibrotic lung changes on imaging and no evidence of TB treatment, these patients should be screened for LTBI, regardless of their other risk factors.
  • Special population: Organ donors should be screened. If donor is deceased, IGRA testing is still possible.

Commonly Associated Conditions

  • HIV infection (see “Initial Tests [lab, imaging]”)
  • Immunosuppression
  • IV drug use and substance use disorders

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