Sample type:Blood

Preparation:You do not need to do anything special to prepare for the sample collection. More details

Test type:In Person  

About the Test

This is an Interferon-Gamma Release Assay (IGRA) TB blood test that detects the immune system’s response to tuberculosis bacteria (Mycobacterium tuberculosis attack the lungs but can also attack any part of the body (e.g., spine, kidneys, brain). Not all TB bacteria infections result in sickness. As a result, two TB-related conditions exist: latent TB infection (LTBI) and TB disease. If not treated properly, TB disease can be fatal.

LTBI is a carrier state of TB that can last for weeks, months, or years before developing into TB disease. Active TB is when tuberculosis bacteria overwhelm a person's immune system, and symptoms start to appear. While it does not differentiate between LTBI and active TB disease, this tuberculosis blood test detects the immune response to TB bacteria which can be the first step in diagnosing either condition. Further testing may be required if the blood test is positive.

With Quest®️, you can buy a TB blood test online and get testing at a nearby location – no doctor’s visit required.

How do I know if this test is right for me?

This test may be right for you if you:

• Have been exposed to a person with a current or past TB infection
• Are from a TB-endemic country (including most countries in Latin America, the Caribbean, Africa, Asia, and Eastern Europe, and Russia)
• Work in high-risk settings, including prisons, healthcare settings, or homeless shelters
• Are HIV positive or have another medical condition that weakens your immune system
• Have an injection drug substance use disorder
• Need evidence of a negative Tuberculosis test for back-to-school, back-to-work, or international travel

What’s Tested

This is a QuantiFERON-TB Gold Plus Assessment, a blood test that aids in the detection of M. tuberculosis bacteria (MTB). Instead of antibodies, it measures a cell-mediated immune (CMI) response to T-cells. CMI is an important component of the body's defense against certain diseases. This test helps to determine when CMI has been activated. Most blood tests examine if antibodies were produced in response to exposure. However, the Tuberculosis Blood Test examines the T-cells that are essential for fighting bacterial infections. Due to this, people vaccinated with the bacillus Calmette-Guérin (BCG) TB vaccine or infected with most environmental mycobacteria should test negative with this blood test.

Understanding your results: The QuantiFERON-TB Gold Plus will provide a positive or negative result. If positive for the bacteria, further testing is necessary to determine whether you have a latent TB infection (LTBI) or TB disease. This test can also provide negative results for those who have received the BCG TB vaccine or have been exposed to environmental mycobacteria.

Signs & Symptoms

Symptoms of an active TB infection may include:

• Chronic cough
• Chest pain
• Fever
• Unexplained weight loss
• Fatigue
• Weakness
• Night sweats
• Coughing up blood

Eligibility

You must be 18 years of age or older to purchase a test on questhealth.com. Purchases not permitted in: AK, AZ, HI.

Preparing for your Sample Collection

You do not need to do anything special to prepare for the sample collection. Fasting is not required for this test.

After the Test

After you provide your specimen, it generally takes few business days to process and release your test results. However, processing times may vary. Your test results will be available in a clear and easy-to-read report. If your results differ from expected ranges, you may receive an alert call from an independent healthcare coordinator. Independent physicians are available to discuss questions or concerns you may have regarding your results.