The QuantiFERON-TB Gold Plus (QFT-Plus) test is a blood test that helps detect Mycobacterium tuberculosis infection. It measures the immune response to TB antigens and is used for both latent TB infection and active TB disease. This test is an alternative to the traditional tuberculin skin test (TST).

The QuantiFERON-TB Gold Plus test involves a blood draw, which carries minimal risk. Potential risks include minor bruising, bleeding, or infection at the puncture site. There are no direct risks from the test itself since it involves laboratory analysis of the blood sample.

Positive: Indicates TB infection (latent or active). Negative: Indicates no TB infection. Indeterminate: Inconclusive result, possibly due to an error in blood collection or processing, or an immune system issue.

Positive: Suggests TB infection. Further evaluation, including a chest X-ray and clinical assessment, is required to distinguish between latent and active TB. Negative: Suggests no TB infection. In the absence of other risk factors or clinical suspicion, no further TB testing is needed. Indeterminate: Indicates that the test did not yield a conclusive result, which may necessitate retesting or alternative diagnostic methods.

A blood sample is required, typically drawn from a vein in the arm. The sample is then processed in the laboratory to measure the immune response to TB-specific antigens.