TB Blood Test | IGRA Tuberculosis Blood Test

Tuberculosis Blood Test

The TB test detects immune response to tuberculosis bacteria (Mycobacterium tuberculosis) in your body. It’s intended for those who have been exposed to TB, have a high risk for contracting TB, or require evidence of a negative TB test result. Read more

Test details

Sample type:

Blood

Preparation:

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

Test type: In Person

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$149.00

+ $6.00 Physician Service Fee

Quantity

What

Detect Mycobacterium tuberculosis, the bacteria that causes Tuberculosis (TB). This is detected in both active TB and latent TB.

Who

Must be 18+ years of age to purchase.

How

Blood

Where

Find a location near you

Schedule an appointment, then visit one of the Quest Diagnostics Patient Service Centers

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.

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

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.

Symptoms of an active TB infection may include:

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

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

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

How it works

Buy a lab test & schedule an appointment

No doctor visit required for purchase. Book a visit to one of 2000+ Quest locations.

Schedule an appointment

Visit Quest for sample collection

Complete your test sample collection during your scheduled appointment.

Get fast results online

Access results online as soon as they’re available.

View results

Get physician support

Discuss your results with an independent physician at no extra cost.

Without treatment, 1 in 10 people with a latent tuberculosis infection will develop TB disease.**

Learn about the two types of tuberculosis tests and how newer blood tests offer much higher accuracy than traditional skin tests.

FAQs

What are the advantages of the QuantiFERON(R)-TB Gold Plus blood test over the Tuberculin Skin Test (TST)?

The results are either positive or negative, and have a lower risk of reader bias when compared to a skin test
Accuracy is not affected by a prior bacillus Calmette-Guérin (BCG) TB vaccination
Only requires a single patient visit (2 to 4 are required for the TST)

Does a previous TST affect the QuantiFERON(R)-TB Gold Plus blood test result?

No, a prior TST does not boost, or provide a false positive for IGRA results, however a previous infection may.

Do vaccinations affect a QuantiFERON(R)-TB Gold Plus blood test result?

Live-virus vaccines may affect IGRA test results. However, the effect of live-virus vaccination on IGRAs has not been studied. Until more information is available, the CDC recommends that IGRA testing for live-virus vaccinations are performed as follows:

Either on the same day as a live-virus vaccination or 4 to 6 weeks after the administration of a live-virus vaccination
At least 1 month after a smallpox vaccination

You should not delay a COVID-19 vaccination due to testing for TB. The COVID-19 vaccine is not a live-virus vaccine. It does not affect the results of the TB blood test.

Can I use my FSA or HSA funds to purchase tests at questhealth.com?

You may be able to use your FSA or HSA funds to purchase lab tests at questhealth.com. Please review your FSA/HSA plan or check with a tax professional to confirm specific requirements for individual eligibility.

Our references

^*Data and Statistics. https://www.cdc.gov/tb/statistics/default.htm

^**Tuberculosis (TB) https://www.cdc.gov/tb/

Tests purchased on questhealth.com are only for individuals who intend to pay directly for testing and do not want to submit a claim for reimbursement under their health insurance.

Tuberculosis Blood Test