QuantiFERON-TB Gold ( QFT )

Note

The QuantiFERON-TB Gold test(QFT) is a whole-blood test for detection of infection to M. tuberculosis. The QFT measures the patient's immunereactivity to M. tuberculosis, the bacterium that causes TB. Blood samples are mixed with TB antigens and incubated for 16 to 24 hours. The antigens include ESAT-6,TB 7.7 and CFP-10,proteins specific to M. tuberculosis complex. If the patient is infected with M. tuberculosis, the patient's lymphocytes will recognize the antigens and release interferon-gamma(IFN-g) in response. Limitations: A negative QuantiFERON-TB Gold result does not preclude the possibility of Mycobacterium tuberculosis infection. Falsely-negative results can be due to the stage of infection (eg, specimen drawn prior to the development of cellular immune response), comorbid conditions that affect immune functions, or other individual immunological factors. QuantiFERON-TB Gold is usually negative in individuals vaccinated with Mycobacterium bovids bacilli Calmette-Guerin. A positive QuantiFERON-TB Gold result should be followed by further medical and diagnostic evaluation for tuberculosis disease. The performance of QuantiFERON-TB Gold has not been evaluated in specimens from: -Individuals with impaired or altered immune functions (HIV infections, transplant patients, those receiving immunosuppressive drugs such as corticosteroids) -Other clinical conditions(eg, diabetes, hematological disorders) -Pregnant women