Mississippi State Department of Health

A Better Test for TB infection


Want a better test for TB infection?

Then you want a TB blood test! The TB blood test is more specific than a TB skin test (less likely to cause a false positive) and it requires only one visit, while a TB skin test may require several visits (four visits over a 10 to 21 day period for a two-step test).

TB blood tests (also called interferon-gamma release assays or IGRAs) measure how the immune system reacts to the bacteria that cause TB. An IGRA is a laboratory test that measures how strongly a person’s immune system reacts to TB bacteria.

Two IGRAs are approved by the U.S. Food and Drug Administration (FDA) and are available in the United States:

  1. QuantiFERON®-TB Gold In-Tube test (QFT-GIT)
  2. T-SPOT® TB test (T-Spot)

Two types of TB blood test results are possible:

IGRAs are the preferred method of testing for TB infection. It should be the only test considered for:

IGRAs can be safely repeated.

Find this page at https://msdh.ms.gov/page/14,0,125,681.html

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