Tuberculosis Blood Test

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 employment, school requirements, or international travel
• Are starting a new medication, such as an immunosuppressant, that may require a negative TB test before you can begin treatment

This test may not be right for you if:

• You believe you have been exposed to TB recently. It can take 8 to 10 weeks after exposure for the immune system to react. Testing too early may result in a false negative 
• You have a persistent cough (3+ weeks), chest pain, or are coughing up blood—seek medical attention

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.

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.

Symptoms of an active TB infection may include:

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

Please note: this test is not recommended if the individual being tested is experiencing symptoms including, but not limited to, the following:    

• A cough lasting more than 2–3 weeks  
• Fever or night sweats  
• Unexplained weight loss  
• Fatigue or loss of appetite 

Purchaser: You must be 18 years of age or older to purchase a test on questhealth.com.

Patient: This test can be performed on patients between 10 and 100 years old. If this test will be performed on someone less than 18 years old:

• The appropriate age bracket needs to be selected during purchase
• Both parent/guardian (hereinafter "parent") and patient information will need to be provided during test registration
• Both parent and patient must be present for sample collection, the parent will need to have their identification available at collection
• Results will be provided to the listed parent

Sample collection: This test requires sample collection at a Quest Diagnostics location or through Quest Mobile® where available, a convenient option for in-home sample collection*. Collection is not available in AZ or HI.

*Check your zip code here for service availability, testing may not be available in all locations. Quest Mobile is currently only available for individuals ages 18+.

Please note: Laboratory testing for children under 18 years of age should always be conducted with the guidance of a qualified healthcare provider. Our tests are designed to support continuity of care, ease of access, and empower families with accessible health information. They are not a substitute for medical evaluation or ongoing care from a pediatrician. Parents should review test results with their child's healthcare provider to ensure appropriate interpretation, follow-up, and treatment in the context of the rest of your child's care. If your child is experiencing symptoms or you have concerns about their health, please contact your pediatrician or seek other medical care immediately.

After you provide your specimen, it generally takes a 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 you have or create a MyQuest® account, you may be able to review your new results there with your other Quest results. Independent healthcare providers are available to discuss questions or concerns you may have regarding your results.

If this test is performed on someone less than 18 years old, the results will be provided to the registered parent.