Tuberculosis Home > TB Test

Blood Test for TB

QuantiFERON®-TB Gold (QFT) is a blood test used to find out if you are infected with TB bacteria (Mycobacterium tuberculosis). The QFT measures the response to TB proteins when they are mixed with a small amount of blood. Currently, few health departments offer the QFT. If your health department does offer the QFT, only one visit is required. Your blood will be drawn at that visit for the test.

Should I Get Tested?

You should get a TB test if:
  • You have spent time with a person known to have active tuberculosis or suspected to have active tuberculosis
  • You have HIV infection or another condition that puts you at high risk for active tuberculosis
  • You think you might have active tuberculosis
  • You are from a country where active tuberculosis is very common (most countries in Latin America and the Caribbean, Africa, Asia, Eastern Europe, and Russia)
  • You live somewhere in the United States where active tuberculosis is more common (such as a homeless shelter, migrant farm camp, prison or jail, or some nursing homes)
  • You inject illegal drugs.

Positive TB Test

If you have a positive reaction to the TB skin test or the QFT, your doctor or nurse may do other tests to see if you have active tuberculosis. These tests usually include a chest x-ray and a test of the phlegm you cough up. Because the TB bacteria may be found somewhere other than your lungs, your doctor or nurse may check your blood or urine, or do other tests. If you have active tuberculosis, you will need to take medicine to cure the disease.
If you have latent TB infection (a positive TB skin test reaction or positive QFT), and you are in a high-risk group (see Causes of Tuberculosis), you need to take tuberculosis medications to keep from developing active tuberculosis. This is called latent tuberculosis treatment. There are several treatment options. You and your healthcare provider must decide which treatment is best for you.
Written by/reviewed by:
Last reviewed by: Arthur Schoenstadt, MD
Last updated/reviewed:
List of references (click here):
Other Articles in This eMedTV Presentation

Topics & Medications


Related Channels

eMedTV Links
Copyright © 2006-2020 Clinaero, Inc.

eMedTV serves only as an informational resource. This site does not dispense medical advice or advice of any kind. Site users seeking medical advice about their specific situation should consult with their own physician. Click Terms of Use for more information.

This site complies with the HONcode standard for trustworthy health information:
verify here.