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Results Line and Enquiries

0203 313 5353


Category Immunology
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


Sample & container 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