Quantiferon-TB Gold Plus

Quantiferon is an ELISA based interferon gamma release assay. Whole blood is stimulated overnight with Mycobacteria Tuberculosis (TB) specific antigens, positive control or a nil control. Interferon gamma concentration from the plasma is measured by ELISA.

Purpose of test

This is similar to the TB ELISpot and is particularly suitable for screening large numbers of healthy people in contact tracing or health care worker screening. This test is not suitable for patients on immunosuppressive drugs or have an immunodeficiency e.g. HIV. TB ELISpot should be performed in these circumstances. Quantiferon assay cannot distinguish between latent and active TB infection.

For detailed recommendations please see NICE clinical guideline 117 (CG117, issued March 2011.

Specimen requirements

Special quantiferon collection tubes are required for this test.

• Patients' blood should either be collected in Lithium Heparin tubes (x3) or the 4 Quantiferon blood tubes - Negative Control (Grey), TB1 (Green), TB2 (Yellow) and Mitogen (Purple).
• Each of tube must contain 1ml of blood (Lithium Heparin (3 tubes, 1ml in each) or Quantiferon (4 Tubes, 1ml in each). More or less than 1ml renders the test inaccurate; such samples will not be tested and repeat samples will be requested.
• The samples must arrive within 16 hours of venepuncture otherwise the test should not be performed.
• Samples must not be refrigerated.

Cost

Price on application

Laboratory turnaround time

10 working days

Laboratory method

Not applicable

Reference range/units

Not applicable

Associated tests

TB ELISpot

Sample stability

Lithium Heparin tubes

16 hours post venepuncture (do not refrigerate or centrifuge)

Quantiferon blood tubes

16 hours post venepuncture or up to 24 hours post incubation (do not refrigerate or centrifuge)

Shipping and storage

See specimen requirements

Further information and contact details

For further information, email immunology.office@nhs.net