Treatment for a Positive TB Quantiferon Gold Test
Diagnostic Evaluation After Positive QFT-G Test
- For individuals with a positive TB Quantiferon Gold test, treatment for latent tuberculosis infection (LTBI) should be initiated after active TB disease has been ruled out with a minimum of chest radiography, as recommended by the Centers for Disease Control and Prevention (CDC) 1, 2
- A positive QFT-G result requires the same medical interventions as a positive tuberculin skin test (TST), according to the CDC 1
- Before initiating LTBI treatment, active TB disease must be excluded through chest radiography, detailed history, physical examination, HIV testing, and bacteriologic studies if TB disease is suspected, as recommended by the CDC 1, 2, 3
- HIV testing is recommended for individuals with a positive QFT-G test due to increased risk and urgency for treating LTBI in HIV-positive individuals, as recommended by the CDC 1, 2
Important Caveats and Pitfalls
- A positive QFT-G test should never be followed by a TST, as it has no added value, according to the CDC 1, 2
- QFT-G has higher specificity than TST, resulting in fewer false positives, especially in BCG-vaccinated individuals, as reported by the CDC 3
- Indeterminate QFT-G results require careful evaluation, including options for repeating QFT-G or administering a TST, as recommended by the CDC 1, 2
- For contacts of infectious TB cases with negative QFT-G results, repeat testing is recommended 8-10 weeks after exposure ends, as recommended by the CDC 1, 2