Description

The QuantiFERON-TB Gold (QFT) test is a blood test that helps detect tuberculosis (TB) by measuring the body's immune response to the bacteria that causes TB.

How it works: The test measures the amount of interferon-gamma (IFN-γ) produced by T cells in the blood after exposure to peptide antigens that mimic proteins found in the bacteria that causes TB. 

What it's used for: The QFT test is used to diagnose latent TB and as an alternative to the tuberculin skin test (TST). 

Results: A positive result indicates a likely infection with TB, but it can't distinguish between active and latent TB. A negative result suggests no TB infection, but it should be repeated in patients with a high likelihood of exposure. 

Advantages: The QFT test is a controlled lab test that doesn't require multiple visits and isn't affected by previous BCG vaccination. It's also more accurate than the TST.

Fasting not required.