What Is the QuantiFERON-TB Gold Test (and Where Can I Get One)?
What Is the QuantiFERON-TB Gold Test (and Where Can I Get One)?
The QuantiFERON-TB Gold test (also called QFT-Plus or IGRA) is a TB blood test that detects an immune response to tuberculosis bacteria. It requires a single blood draw — no return visit to have a result "read" — and it is not affected by prior BCG vaccination. It's widely accepted for school and healthcare compliance, costs around $100–$200, and can be ordered online with a physician's order included, drawn at Quest or LabCorp locations nationwide.
What Exactly Is the QuantiFERON-TB Gold Test?
QuantiFERON-TB Gold (manufactured by Qiagen) is a brand name for an Interferon-Gamma Release Assay (IGRA). It belongs to a class of TB tests that measure how your immune system responds to proteins specific to Mycobacterium tuberculosis, the bacterium that causes TB.
Here's how it works in plain terms:
- A blood sample is drawn and placed in tubes containing TB antigens (proteins).
- If your immune system has previously been exposed to TB, your white blood cells will release a protein called interferon-gamma (IFN-γ) in response.
- The laboratory measures the amount of interferon-gamma produced. A significant response = positive result.
This process happens entirely in the lab — you never need to return to a clinic for a reading. Results typically come back within 1–3 business days.
The current generation of the test is called QuantiFERON-TB Gold Plus (QFT-Plus), which adds a second antigen tube for improved sensitivity. Most labs and documentation simply call it "QuantiFERON Gold" or "QFT."
QuantiFERON Gold vs. TB Skin Test: Key Differences
| Feature | QuantiFERON Gold (IGRA) | TB Skin Test (PPD/Mantoux) |
|---|---|---|
| Visits required | 1 visit (blood draw only) | 2 visits (inject + read 48–72h later) |
| Affected by BCG vaccine | No — highly specific to TB | Yes — BCG can cause false positives |
| Reader subjectivity | Objective lab measurement | Subjective — depends on clinician reading |
| Turnaround for results | 1–3 business days (lab) | Read in-person at 48–72 hours |
| 2-step protocol | Not applicable | Required for some healthcare baseline screens |
| Typical cost (out of pocket) | $100–$200 | $40–$100 |
| Available via online order | Yes — order + Quest/LabCorp draw | Limited — must be injected in person |
Who Should Choose the QuantiFERON Gold Blood Test?
The QuantiFERON Gold test is the preferred choice for several groups:
- People vaccinated with BCG — BCG (Bacillus Calmette-Guérin) is a TB vaccine used in many countries outside the U.S. (common in India, Mexico, Brazil, China, the Philippines, and throughout Africa and Eastern Europe). BCG frequently causes a positive TB skin test, even decades later, creating a problem for healthcare compliance. The QuantiFERON test uses antigens not present in BCG, so it gives an accurate result regardless of BCG history.
- Healthcare students and workers who need fast documentation — One visit, no return appointment, digital results in days. Hospitals and nursing programs increasingly require or accept the IGRA specifically because it's more efficient.
- Anyone with a busy schedule — The single-visit model means you don't have to plan around a 48–72 hour return window at a clinic.
- People who need a TB test ordered without a doctor's visit — Online services that include a physician order make the QFT-Gold accessible without scheduling a clinic appointment.
- Travelers and international workers — Individuals spending time in high-TB-burden countries are often screened with the IGRA.
Order the QuantiFERON Gold TB Blood Test online →
The BCG Vaccine and TB Testing: Why It Matters
If you received the BCG vaccine as a child (very common in countries outside the U.S.), a TB skin test (PPD) may show a positive reaction simply because of the BCG — not because you have TB. This causes unnecessary concern, additional testing, and sometimes barriers to school or employment enrollment.
The QuantiFERON Gold test does not react to BCG. Its antigens (ESAT-6 and CFP-10) are encoded by genes absent in BCG strains and most nontuberculous mycobacteria. This means a positive QuantiFERON result in a BCG-vaccinated person is a true signal of TB exposure, not a vaccine artifact.
The CDC recommends IGRA testing as preferred for BCG-vaccinated individuals and for those unlikely to return for a skin test reading.
What Does a QuantiFERON Gold Result Mean?
- Negative: No significant interferon-gamma response detected. This indicates no evidence of TB infection. Most people testing for school or work compliance receive a negative result.
- Positive: Significant immune response detected. This suggests TB infection (most likely latent TB, not active disease). A positive result requires follow-up with a healthcare provider, typically a chest X-ray and clinical evaluation.
- Indeterminate: The test result could not be interpreted — either the positive control didn't respond (suggesting immunosuppression or poor specimen handling) or the negative control showed too much background. An indeterminate result usually means the test should be repeated.
Important: A positive QuantiFERON Gold result does not mean you have active, contagious tuberculosis disease. The majority of people with TB infection have latent TB, which is not contagious and can be treated with preventive therapy. Active TB disease involves symptoms like cough, fever, and weight loss and requires different treatment.
How Accurate Is the QuantiFERON Gold Test?
Studies comparing IGRA tests to TB skin tests and culture-based gold standards show QuantiFERON Gold has:
- Sensitivity (ability to detect true TB infection) of approximately 80–90% in most studies
- Specificity (ability to correctly identify non-infected individuals) of approximately 95–99%, which is significantly higher than the skin test in BCG-vaccinated populations
No TB test is perfect. In people with severely compromised immune systems (e.g., HIV infection, chemotherapy), both IGRA and skin tests may underperform. A healthcare provider should interpret results in context of the full clinical picture.
Where Can I Get a QuantiFERON Gold Test Near Me?
Several paths exist to access QuantiFERON Gold testing:
Option 1: Order Online → Draw at Quest or LabCorp
This is the most convenient route for most people. Services like SchoolTiters ($149) include a physician's order; you purchase online and walk into any participating Quest Diagnostics or LabCorp patient service center — no doctor's appointment needed. Results arrive electronically in 1–3 business days. SchoolTiters also offers a version specifically for minors: the TB Blood Test QuantiFERON Gold for Minors ($239.88).
Option 2: Quest Health Direct
Quest Health (questhealth.com) offers direct-to-consumer lab testing including IGRA. Prices vary; physician order is included. Draw at Quest patient service centers nationwide.
Option 3: Your Primary Care Doctor
Your physician can order a QuantiFERON Gold test and have it processed at any major laboratory. If you have insurance, this is often covered as a preventive or pre-employment screening.
Option 4: Occupational Health Clinics
Many hospitals and large employers operate occupational health clinics that offer QFT testing for employee credentialing. These are typically only accessible if you're affiliated with that organization.
Option 5: Any Lab Test Now
Any Lab Test Now has physical locations that offer direct IGRA testing. Find a location at anylabtestnow.com.
Is the QuantiFERON Gold Right for School or Compliance Requirements?
For students entering nursing, medical, dental, dental hygiene, physical therapy, or other clinical programs, the QuantiFERON Gold is generally accepted as equivalent to the skin test. Most healthcare employer credentialing and hospital systems also accept it.
One exception: if your program specifically requires a 2-step PPD (two rounds of skin testing), the blood test cannot substitute — the 2-step protocol is specific to the skin test. However, many programs will accept the IGRA in place of the 2-step if you ask. Check your requirement form or contact the program directly.
If you need both a TB test and immunity titers (MMR, hepatitis B, varicella) for a healthcare program, SchoolTiters offers a bundled Immunity Panel + TB Blood Test ($279) that covers all requirements in one order.
Order QuantiFERON Gold online — results in 1–3 days →
Frequently Asked Questions
Is QuantiFERON Gold the same as a TB blood test?
Yes. "QuantiFERON Gold" and "TB blood test" are used interchangeably. The formal category is IGRA (Interferon-Gamma Release Assay). QuantiFERON-TB Gold Plus is the most widely used IGRA brand in the United States, processed by Quest Diagnostics and LabCorp among others.
Do I need to fast before a QuantiFERON Gold blood test?
No fasting is required for the QuantiFERON Gold test. It is a standard blood draw and has no dietary restrictions.
Can I get a QuantiFERON Gold test near me without seeing a doctor first?
Yes. Online ordering services like SchoolTiters, Quest Health Direct, or Request A Test include a physician's order with the test, so you don't need to schedule a separate doctor's appointment. You take a requisition form to a nearby draw site.
How long is a QuantiFERON Gold result valid for school or work requirements?
Most schools and healthcare employers accept a negative IGRA result from within the past 12 months. Some require annual testing. Always check your specific program's requirement form for the validity window.
What happens if my QuantiFERON Gold test is positive?
A positive result indicates TB infection (most likely latent TB). You'll need to follow up with a healthcare provider who will evaluate your history, likely order a chest X-ray, and discuss whether preventive treatment is appropriate. A positive result does not automatically disqualify you from school or work — institutions typically follow CDC guidelines for managing latent TB in healthcare settings.
Does the QuantiFERON Gold test work for children?
The IGRA is approved and used for children age 2 and older. For minors, SchoolTiters offers a dedicated QuantiFERON Gold for Minors ($239.88) product that includes appropriate handling and parental consent documentation.
This article is for general information only and is not medical advice. TB test interpretation and follow-up should always involve a licensed healthcare provider familiar with your individual health history.
