QuantiFERON®-TB Gold is a blood test used for screening and diagnosis of latent tuberculosis infection (LTBI) and tuberculosis (TB) disease. It is an alternative to the traditional tuberculin skin test (TST) for detecting Mycobacterium tuberculosis infection.
Here’s an overview of the QuantiFERON®-TB Gold test:
Test Process: The QuantiFERON®-TB Gold test involves collecting a blood sample from the individual being tested. The sample is then processed in a laboratory to assess the immune response to M. tuberculosis antigens.
Detection of Interferon-gamma (IFN-γ): The test measures the production of interferon-gamma (IFN-γ) by specific immune cells (T-cells) in response to M. tuberculosis antigens. The antigens used in the test include peptides derived from TB-specific proteins, such as ESAT-6 and CFP-10.
Positive and Negative Results: The QuantiFERON®-TB Gold test provides a numerical result based on the amount of IFN-γ released in response to the M. tuberculosis antigens. A positive result indicates the presence of an immune response to TB and suggests either latent TB infection or active TB disease. A negative result suggests the absence of an immune response to TB.
Advantages: The QuantiFERON®-TB Gold test offers several advantages over the traditional tuberculin skin test. It is a single-visit test that provides results within 24 to 48 hours, eliminating the need for a second visit for result interpretation. It is not affected by prior BCG vaccination, which can cause false-positive results with the tuberculin skin test. The blood sample collection is also simpler and less subjective than the TST.
It’s important to note that the QuantiFERON®-TB Gold test is not diagnostic for active TB disease. If the test result is positive or if there are symptoms suggestive of active TB, further diagnostic evaluation, such as chest X-ray and sputum culture, may be required.
The QuantiFERON®-TB Gold test is commonly used in healthcare settings, occupational health, immigration screening, and other situations where TB screening is necessary.