LTBI Risk Assessment Tools and Treatment Guidelines

Avoid testing persons at low risk: Routine testing of persons without risk factors is not recommended and may result in unnecessary evaluations and treatment because of falsely positive test results.

Most patients with LTBI should be treated: Most persons with risk factors and a positive IGRA or TST should be treated for LTBI after active TB disease has been excluded. Evaluation for active TB includes physical exam, symptom screen, chest x-ray and if indicated, sputum collection.

Definition of a positive tuberculin skin test: The definition of a positive tuberculin skin test depends on a person’s prior probability of having LTBI and the person’s risk of developing active TB.

≥5 mm of induration

· Persons with HIV infection and other immunosuppressed individuals.

· Recent contacts to an active case of pulmonary or laryngeal TB.

· Persons with fibrotic changes seen on chest radiograph consistent with TB.

≥10 mm of induration

· All persons except those listed above

NOTE: The CDC recommends using a 15 mm cutoff for low risk reactors. However, in California, using a 10mm cutoff is the standard due to the higher incidence of TB in the state compared to other parts of the US.