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Who should be tested for latent tuberculosis infection (LTBI)?

Individuals with increased risk of new TB infection

Close contacts of patients with untreated active respiratory TB*

Casual contacts of patients with untreated active respiratory TB*

People who use illicit drugs

Residents or employees of a homeless shelter or correctional facility

Health care workers in some circumstances^¶

Individuals with increased risk of reactivation^Δ

High risk (test all patients)

HIV infection (any stage of illness)

Transplant, chemotherapy, or other major immunocompromising condition

Lymphoma, leukemia, head and neck cancer

Abnormal chest radiograph with apical fibronodular changes typical of healed TB (not including granuloma)

Silicosis

Renal failure (requiring dialysis)

Treatment with TNF-alpha inhibitors

Moderate risk (test patients in groups with increased prevalence of LTBI)^◊

Diabetes mellitus

Systemic glucocorticoids (≥15 mg/day for ≥1 month)^§

Slightly increased risk (test patients in groups with increased prevalence of LTBI)^◊

Underweight (<85 percent of ideal body weight); for most individuals, this is equivalent to BMI ≤20

Smoking cigarettes (≥1 pack/day)

Chest radiograph with solitary granuloma

Individuals born in or former residents of countries with high incidence of TB disease (without other risk factors listed above)^¥

Only those who would benefit from treatment should be tested, so a decision to test presupposes a decision to treat if the test is positive. Individuals with very low likelihood of LTBI should not be tested routinely, as the yield of testing is low and the likelihood of a false-positive test becomes more important.
Local epidemiologic patterns and risk groups may vary; consult local or state health departments for more information about populations with increased prevalence of latent TB in the local community.
The approach to LTBI testing should be individualized in older patients at lower risk of reactivation. The relationship between the risk of adverse events and increasing age is well documented for isoniazid. Thus far, data are insufficient to determine appropriate age thresholds for LTBI testing if individuals with a positive test are treated with a shorter rifamycin-based regimen. Until further data on the age-related risks of adverse events with these regimens are available, it is reasonable to adhere to the same cautions as for isoniazid.

TB: tuberculosis; TNF: tumor necrosis factor; BMI: body mass index; CDC: United States Centers for Disease Control and Prevention; TST: tuberculin skin test.
* Close contacts are defined by the CDC as individuals with at least 4 hours of contact per week. This includes those living in the same household or frequent visitors to the house; it may also include contacts at work or school. Casual contacts are defined by the CDC as individuals with less than 4 hours of contact per week. This may include health care workers and/or contacts at work or school.
¶ In regions with low TB incidence rate, health care workers in facilities with low TST conversion rate need not undergo routine serial TB screening. Serial TB screening may be reasonable for HCWs at increased risk for occupational exposure to TB (such as pulmonologists or respiratory therapists) or for health care workers in certain settings (such as emergency departments). Refer to the UpToDate topic on diagnosis of LTBI for further discussion.
Δ An individual with a false-negative test resulting from faded immune memory who then receives immunosuppression (such as a TNF inhibitor) may be at high risk of reactivation disease. Such individuals warrant a single test if interferon-gamma release assay is used; however, use of the TST warrants a two-step test.
◊ In general, groups with increased LTBI prevalence include homeless individuals, injection drug users, contacts of active TB cases, and foreign-born individuals who immigrated as adults from countries with TB incidence >100/100,000 (this includes most countries in Africa and Asia, many countries in Eastern Europe, Central America and South America, plus Haiti and the Dominican Republic).
§ The CDC recommends skin testing for all patients in this category. However, population-based studies demonstrate that the relative risk for development of active tuberculosis in this category is moderate (2 to 4 times that of healthy individuals). Therefore, an age cutoff of ≤65 is indicated, so that potential risks of isoniazid toxicity in older adult patients do not outweigh potential benefit. (Refer to the separate UpToDate table summarizing relative risk for development of active tuberculosis).
¥ Individuals born in or former residents of countries with high TB incidence (>100/100,000) are an additional category of individuals with increased prevalence of TB infection. In the United States and the United Kingdom, guidelines favor LTBI testing for such individuals; in Canada, guidelines favor LTBI testing only for groups within the immigrant population who have additional risk factors for progression to active disease.

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