Test Background This assay detects interferon-gamma (IFN-γ) secretion in response to stimulation with Mycobacterium tuberculosis antigens. A positive test indicates presence of TB infection but cannot be used to distinguish active disease from latent infection. The negative predictive value of this test for TB infection is 98 %.
Clinical Indications TB infection
Reference Range Negative
Sample Required 8mL sodium citrate (pale blue top) or 10 mL heparin (green top)
Samples must be received in the laboratory (Charing Cross) by 2pm Monday to Friday for the test to be performed
Sample Volume See above
Turnaround Time 4 days