What is QFT git test?
QuantiFERON-TB Gold (QFT) is a simple blood test that aids in the detection of Mycobacterium tuberculosis, the bacteria which causes tuberculosis (TB). QFT is an interferon-gamma (IFN-γ) release assay, commonly known as an IGRA, and is a modern alternative to the tuberculin skin test (TST, PPD or Mantoux).
What does a positive QuantiFERON test mean?
You have a positive Tuberculin Skin Test (TST) or QuantiFERON blood test: what does this mean? If your TST (Mantoux) or Quantiferon blood test was found to be positive, this means you have a latent TB infection, but usually not the active disease.
How is QuantiFERON test done?
The QFT system uses specialized blood collection tubes, which are used to collect whole blood. Incubation of the blood occurs in the tubes for 16 to 24 hours, after which, plasma is harvested and tested for the presence of IFN-γ produced in response to the peptide antigens.
What does a positive IGRA test mean?
A positive IGRA test means that you have been infected with tuberculosis. This does not mean that you are ill. It is believed that approximately 1/3 of the world’s population are IGRA positive without suffering from tuberculosis, meaning they have what is called latent tuberculosis infection.
What to do if TB test is positive?
What if I have a positive test for TB infection? If you have a positive reaction to the TB blood test or TB skin test, your doctor or nurse will do other tests to see if you have TB disease. These tests usually include a chest x-ray. They may also include a test of the sputum you cough up.
Can IGRA detect active TB?
The IGRA blood test can detect M. tuberculosis infections, but cannot distinguish between latent and active infections. Additional tests, such as AFB testing, are required to help establish a diagnosis of an active TB infection.
What is the normal range of TB?
Table 2
| QFT result by category | Total number tested | Incident TB (3–24 months) |
|---|---|---|
| Negative (<0.2 IU/ml) | 28976 | 14 |
| Borderline negative (0.2–0.34 IU/ml) | 1664 | 2 |
| Borderline positive (0.35–0.99 IU/ml) | 1992 | 11 |
| Positive (>0.99 IU/ml) | 6712 | 65 |
How often do you need a QuantiFERON test?
In contact investigations, negative results obtained prior to 8 weeks typically should be confirmed by repeat testing 8–10 weeks after the end of exposure.
Can TB go away on its own?
Pulmonary tuberculosis frequently goes away by itself, but in more than half of cases, the disease can return.