It has been estimated that up to 5% of the population of the United States between 18 and 65 years of age have latent tuberculosis infections (LTBI), and approximately 10,000 new cases of active tuberculosis were reported in the US in 2015, according to a recent article reported in the Journal of the American Medical Association. Approximately 30% of individuals exposed to tuberculosis will develop LTBI. Left untreated, 5% to 10% of those with LTBI will develop active tuberculosis.
According to the United States Preventive Services Task Force (USPSTF), screening tools for LTBI exist, including the tuberculin skin test (TST) and the interferon-gamma release assays (IGRAs). Because many patient and system factors may determine the selection of the appropriate screening test, the Centers for Disease Control and Prevention recommends screening with either test, but not both. Testing with IGRAs may be preferable for persons who have received a BCG vaccination or those who are unlikely to return for TST interpretation.
Treatment of patients with LTBI provides a moderate net benefit (treatment of up to 314 patients with LTBI would be required to prevent 1 case of active tuberculosis) with no harm.
Populations at increased risk for LTBI include the following:
- Persons who were born in, or are former residents of, countries with increased TB prevalence;
- Persons who live in, or have lived in, high-risk congregate settings, such as homeless shelters and correctional facilities.
Clinicians can check with their local or state health departments for more information about populations at risk in their community.