Treatment of Latent Tuberculosis Infection (LTBI)
Managing Patients with Positive Tuberculin Skin Tests (TSTs) or Interferon Gamma Release Assays (IGRAs)
A chest x-ray must always be obtained when there is a positive TST or IGRA to rule out active disease.
If the chest x-ray is not suggestive of active TB, the patient is a candidate for latent TB treatment (this was previously called “prophylaxis”.)
There are three regimens that can be used to treat LTBI:
Of the LTBI treatments available, the preferred methods are the short-course treatment options: either rifampin daily for 4 months or isoniazid plus rifapentine weekly for 12 weeks.
If a rifamycin-based regimen is not an option (due to drug interactions or intolerance), use isoniazid daily for 9 months.
San Mateo County follows treatment recommendations set forth by the California Tuberculosis Controller’s Association (CTCA) adapted from the Centers for Disease Control (CDC). Please review the 2019 CTCA Guidelines for LTBI.
For contacts to a case of drug resistant tuberculosis, specific treatment recommendations may be made by San Mateo County’s TB program, depending on the susceptibility of the organism to which the contact was exposed.
Remember, we are available for consultation! 650-573-2346