What is QuantiFERON-TB Gold Plus?

QFT-Plus is a blood test that can help detect TB infection.

QFT-Plus is a major scientific advance over the 100-year-old TB skin test (sometimes called Mantoux, tuberculin skin test, TST or PPD). QFT-Plus provides greater accuracy and a more reliable result in a single patient visit.

In what situations should QFT-Plus be used?

QFT-Plus can be used in all situations in which the TB skin test has been used in the past. QFT-Plus can also be used to confirm a positive skin test result.

How does QFT-Plus work?

QFT-Plus uses four unique blood collection tubes that enable immediate exposure of viable blood lymphocytes (immune cells) to highly specific TB antigens and test controls coated on the inner surface of the tubes. Exposure to these TB antigens causes lymphocytes (specifically CD4 and CD8 T cells) to produce a quantifiable small molecule called Interferon-γ (IFN-γ). Interferon-gamma production is correlated to the presence or absence of TB infection, and this IFN-γ response is measured in a laboratory to aid in the diagnosis of TB infection.

For more information visit the QuantiFERON Technology page.

What does QFT-Plus testing involve?

QFT-Plus is convenient and only involves collection of a blood sample, which is then sent to a laboratory for analysis.

What are the benefits of QFT-Plus?

QFT-Plus is a highly accurate test with >97% specificity for detection of TB infection.

QFT-PlusTB skin test
One visit to the doctorTwo visits to the doctor
A small sample of blood is takenTuberculin is injected into the skin
Results are unaffected by the prior TB (BCG)vaccination Results may be affected by the BCG vaccine
Results determined in a laboratoryResults determined by subjective/visual assessment

How are QFT-Plus results interpreted?

QFT-Plus is one of the many tools your doctor may use to determine whether TB infection is present.

There are three possible QFT-Plus results:

  • Positive – suggests that TB infection is likely
  • Negative – suggests that TB infection is unlikely
  • Indeterminate – suggests the need for further investigations or repeat testing

Your healthcare provider will explain your QFT-Plus results to you. In addition to your QFT-Plus result, your healthcare provider will take into account essential information such as your medical history, your risk of exposure to TB, and other clinical results that may be ordered.

Are there any risks with having a QFT-Plus test?

No, there are no risks associated with having the test apart from the slight discomfort of having a blood sample taken.

How long before I get results?

A QFT-Plus result can be available in as little as 24 hours. However, this may vary depending on the preferences of both the healthcare provider and the laboratory.

What do I do if I have a positive QFT-Plus result?

A positive result only indicates the likelihood of infection and does not mean you have active tuberculosis or that you are contagious. Active tuberculosis is diagnosed through a combination of laboratory tests (bacteriological testing), X-rays and other clinical evaluations. Your doctor will advise you on the next steps if you have a positive QFT-Plus result.

Product claims may differ from country to country based on regulations and approvals. Contact your country representative for further details.

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