Lab test

TB Gold Blood Test - QuantiFERON Tuberculosis Lab Test

A tuberculosis blood test, or interferon-gamma release assay, checks whether the immune system has been exposed to the bacterium that causes TB.

Typical price

From $199

Results

1-3 business days

Preparation

See preparation notes below

Sample

Blood draw or sample collection at a local center

A tuberculosis blood test, or interferon-gamma release assay, checks whether the immune system has been exposed to the bacterium that causes TB. It measures the release of interferon-gamma after blood is mixed with specific TB antigens. Clinicians use it to screen people at risk, test close contacts, and check healthcare or travel-related exposure without a skin test.

• Interferon-gamma response to TB antigens (ESAT-6, CFP-10, TB7.7) A marker of immune sensitization to TB, measured by an interferon-gamma release assay.

• People with close contact with someone who had TB.
• Individuals from or traveling to areas where TB is more common.
• Healthcare and other workers with TB exposure risk.
• People with weakened immune systems.
• Those being screened before certain procedures or medications.

• No fasting is required for a TB blood test.
• Take usual medications unless told otherwise.
• Tell the provider about prior TB tests or treatment.
• A standard blood draw is used; the sample must be processed promptly.
• Share any immune conditions or medications that could affect results.

A positive interferon-gamma result indicates the immune system has likely been exposed to TB and usually prompts further evaluation for active or latent infection. A negative result makes exposure less likely but can be affected by immune status and timing. The test does not distinguish latent from active TB by itself. Discuss the result with a healthcare provider.

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