QuantiFERON ® -TB Gold assay

The QuantiFERON ® -TB Gold assay detects CMI responses in-vitro to tuberculosis infection by measuring interferon-gamma (IFN-G) harvested in plasma from whole blood incubated with the M. tuberculosis-specific antigens, ESAT-6 & CFP-10.

The QuantiFERON ® -TB Gold test is performed in two stages.
In the first stage, aliquots of heparinised whole blood are incubated with ESAT-6, CFP-10, T cell mitogen (PHA) and negative control antigens. Following a 16 to 24 hour incubation, the plasma is harvested.
In the second stage, the amount of IFN-? in the plasma samples is quantified by enzyme-linked immunosorbent assay (ELISA). Results for test samples are reported in International Units relative to a recombinant human IFN- ? standard preparation.

An IFN-G response to either ESAT-6 or CFP-10 above the test cut-off is considered indicative of M. tuberculosis infection.

This test should be considered as an alternative to the Mantoux test, but has the advantages that it can be used to detect latent TB infection in patients who have been vaccinated with BCG and have a positive Mantoux test. It can also be used when a Mantoux test is contraindicated.

Please note this test is primarily intended to detect latent infection with M. tuberculosis, but not for the diagnosis and management of active tuberculosis. Should active TB be suspected, culture (and/or PCR testing) of appropriate clinical specimens is still necessary for a definitive diagnosis.

This assay will not detect infection with M. bovis BCG strains used for vaccination or immunotherapy.

Specimen collection advice:
Gently mix the heparin blood tube (minimum 5mL venous blood) by inverting the tube several times to dissolve the heparin, and transport to the laboratory at ambient temperature (22°C ± 5°C). Do not refrigerate or freeze the specimen.
NB: Blood should be incubated with stimulation antigens as soon as possible (within 10 hours) after collection. Specimens should reach the laboratory by no later than 4pm Monday to Friday. Specimens arriving after hours may be rejected.
Please contact the laboratory for advice if there is likely to be any delay in specimen transport on 93422670.

For further information on this test and result interpretation, test limitations & references, please download the package insert from the downloads panel

This package insert has been posted with the permission of Cellestis