Gamma Interferon (Quantiferon)
This test measures gamma interferon produced by T cells in
response to mycobacterial peptides
Specimen transport: Samples should reach the
laboratory within four hours of being drawn. The test is not
performed on Fridays. An alternative for hospitals outside Greater
Manchester is to incubate the samples locally, centrifuge them and
send the supernatant. This should only be done after discussion
with laboratory staff.
Repeat frequency: At significant change of
Special precautions: Three special sample tubes
are required for this test. They can be obtained from Immunology.
These tubes are vacutainer and will draw 1ml of blood. Please do
not take the caps off the tubes. Please do not overfill the tubes.
Read and follow the accompanying instructions carefully.
Normal reference range: Neg
Volume and sample type: The test requires
special sample tubes obtainable from Immunology (0161 276 6440)
Turnaround time (calendar days from sample
receipt to authorised result): Median - 7, 95th percentile - 11
Indications for the test: The test is used to
help diagnose latent TB infection and is indicated in individuals
with a positive delayed hypersensitivity skin test.
Factors affecting the test: The test is less
reliable on patients with suspected active TB (as opposed to latent
TB), infants and in immune deficiency states.
Clinical workstation reference: GIFN
(Last updated October 7th