PRINCIPLE , PROCEDURE AND INTERPRETATION OF QUANTIFERON TB GOLD

1. QFT is a simple blood test that used for detection of
mycobecterium tuberculosis, the bacteria which causes
tuberculosis (TB).

3. SAMPLE COLLECTION TUBE FOR QUANTIFERON TB GOLD

8. PRINCIPLE OF QUANTIFERON TB GOLD
• After 16 to 24 hour incubation period, the tubes are centrifuged, the
plasma is removed and the amount of IFN-y (IU/ml) measured by
ELISA.
• Nil The baseline interferon gamma level produced by the patient’s
lymphocytes.
• Tb Antigen-Nil (TbAg-Nil) The level of interferon-gamma production
by the patient’s lymphocytes due to stimulation by M. tuberculosis
antigens minus the Nil (i.e., basal) level of interferon-gamma.
• Mitogen-Nil The maximum non-specific stimulated interferongamma
level that may be produced by the patient’s lymphocytes minus the Nil
(i.e., basal) level of interferon-gamma.

9. PROCEDURE OF QUANTIFERON TB GOLD

12. A. During sample collection
1. In proper mixing / filling : Reduced lymphocytes activity.
2. Reduced incubation time (less than 16 to 24 hour) : Reduced lymphocytes activity.
B. During test procedure
1. Kit have expired.
2. Incomplete washing of plate.
3. Enzyme substrate solution contaminated.
4. Incorrect plate reader filter used.