Management of Positive Tuberculin (TB) Titer

Initial Evaluation After Positive TST

All individuals with a positive TST result (≥5 mm induration) should undergo chest radiography and clinical evaluation to exclude active TB disease, as recommended by the Centers for Disease Control and Prevention (CDC) 1, 2
Patients with symptoms suggestive of TB should promptly undergo chest radiography and clinical evaluation regardless of their TST status, according to the CDC 1
Collection of specimens for mycobacteriologic testing (e.g., sputum) should be considered on a case-by-case basis and is not routinely recommended for healthy contacts with normal chest radiographs, as stated by the CDC 3

A positive TST is defined as ≥5 mm induration for HIV-infected persons, recent contacts of TB cases, and persons with organ transplants or immunosuppression, as defined by the CDC 1, 3, 4
A positive TST is defined as ≥10 mm induration for residents of high-risk congregate settings, according to the American College of Rheumatology 5

All HIV-infected persons with a positive TST but no evidence of active TB should receive treatment for latent TB infection, as recommended by the CDC 1
Treatment options for latent TB infection include isoniazid daily or twice weekly for 9 months (preferred regimen), rifampin daily for 4 months, rifabutin daily for 4 months (alternative when rifampin cannot be used), and rifampin and pyrazinamide daily for 2 months (caution due to hepatotoxicity risk), as stated by the CDC 1

Patients on immunosuppressive therapy (including biologics) should receive treatment for latent TB infection before continuing or initiating biologic therapy, as recommended by the American College of Rheumatology 5, 4
Children under 5 years with positive TST should receive a full diagnostic medical evaluation, including chest radiography, as stated by the CDC 3, 6

Patients receiving isoniazid should also receive pyridoxine (vitamin B6) to prevent peripheral neuropathy, especially HIV-infected persons, as recommended by the CDC 1
Liver function tests should be monitored every 2-4 weeks during treatment, as stated by the European League Against Rheumatism 7
Patients should be educated about symptoms of hepatotoxicity (nausea, vomiting, jaundice), as recommended by the European League Against Rheumatism 7, 8

Interferon-gamma release assays (IGRAs) like QuantiFERON-TB Gold and T-SPOT.TB may be preferred over TST in BCG-vaccinated populations due to higher specificity, as stated by the European Respiratory Society 9
The positive predictive value of TST for development of active TB is generally poor, while the negative predictive value is high, as reported by the European Respiratory Society 9