Quantiferon TB Gold, Blood

Diagnostic Use

QuantiFERON-TB Gold Plus (QFT) is a blood test assisting in the detection of Mycobacterium tuberculosis (MTB), the bacteria which causes tuberculosis (TB).
QFT is an interferon-gamma (IFN-γ) release assay (IGRA). QuantiFERON-TB Gold Plus (QFT) is an indirect test for M.tuberculosis infection (including disease) and is intended for use in conjunction with other diagnostic evaluations (radiography) and clinical evaluation and risk assessment.
QFT has a limited role in the diagnosis of TB. Positive Tuberculin skin tests and IGRA results do not distinquish between active TB disease and Latent TB infection (LTBI). A positive IGRA may help support a diagnosis of active TB in the appropriate clinical circumstance but is never conclusive.

Interferon Gamma Release Assay testing in patients aged five years and under require authorisation by a paediatric infectious diseases specialist or a microbiologist.
Specialist endorsement should be noted on the request form.Blood for IGRA testing can be taken on the paediatric day ward by paediatric registrars. For all other non-paediatric collections it is preferred to have the blood collected by phlebotomists.

The collection times for the test are strictly Monday-Thursday 0800-1600hrs.
No collection on Friday, Sat, Sun or Public Holidays.
It is important for test performance that the correct collection and initial processing procedures are strictly adhered to (please see the link to Test instructions below).
The QuantiFERON assay-specific collection tubes (4 set), as supplied by the laboratory, must be used. No other tubes are acceptable.
It is essential for the blood volume collected into each tube to be exactly 1ml.


Microbiology - Serology

Delphic Registration Code


Laboratory Handling


Monday-Thursday collects only. (No Friday, Sat, Sun or Public holiday collects) Bloods must be taken strictly no later than 16:00hrs. Specialised tubes with correct draws critical. *Do Not Refrigerate* Refer to "resources" below.


Immediate delivery to Lab at Room Temperature for correct incubation. *Do Not Refrigerate*


Requires incubation according to protocol before separating.


Samples to be inverted x 10 and incubated at 37C between 1100 - 1700.


TB Gold

Turnaround Time

5 days