T-Spot TB Test

Specimen Required

8cc-Lithium Heparin Vial (Two Vials)

Fasting Required

Purpose of the Test

The T-Spot TB test is a blood test used to detect the presence of tuberculosis (TB) infection. It measures the immune response to the bacteria that cause TB, Mycobacterium tuberculosis, by detecting the T cells in the blood that have been activated by the bacteria. The test is used to aid in the diagnosis of active TB disease and latent TB infection (LTBI).

When this test is required

The T-Spot TB test is requested when a person has symptoms of TB disease or has been exposed to someone with TB. It is also used as a screening test for people at high risk of developing TB, such as healthcare workers, immigrants from high-prevalence countries, and people with HIV/AIDS or other immunocompromising conditions.

What the Test Detects

The T-Spot TB test measures the number of T cells in the blood that have been activated in response to Mycobacterium tuberculosis. The test uses an enzyme-linked immunospot (ELISPOT) assay to detect the presence of interferon-gamma (IFN-gamma) released by T cells in response to antigens specific to M. tuberculosis.

Preparation for the Test

No special preparation is required for the T-Spot TB test.

Sample Requirements

The T-Spot TB test requires a blood sample, which is collected using a standard blood draw from a vein in the arm.

Additional Notes

The T-Spot TB test is a relatively new test and is not available in all healthcare settings. It is more expensive than the traditional TB skin test and requires a laboratory to perform the ELISPOT assay. The T-Spot TB test cannot be used to determine if a person is contagious or not, and additional tests, such as sputum culture, are required to confirm the diagnosis of active TB disease.

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