Quick Facts
- Sample: Blood (single draw)
- Fasting: No fasting required
- Turn-around: 2–5 business days. May take longer based on weather, holiday, or lab delays.
Benefits
- Convenient single blood draw — no return visits required like skin tests
- Accurate results — 94% sensitivity and 97% specificity for TB detection (Mayo Clinic 2025)
- Unaffected by BCG vaccination — eliminates false positives from prior TB vaccination
- Fast turnaround — results in 2–5 days vs. weeks for other methods
- Detects both latent and active TB — comprehensive screening in one test
- No doctor visit needed — order directly through Walk-In Lab
Who Is This Test For?
- Healthcare workers requiring regular TB screening for employment
- Recent immigrants from high TB-prevalence countries needing clearance
- Immunocompromised individuals at higher risk for TB infection
- People with TB exposure through work, travel, or close contact
- Students and employees needing TB clearance for school or work
- Anyone with TB symptoms like persistent cough, night sweats, or unexplained weight loss
How It Works – Just 3 Steps
- Order online — no appointment needed, just visit any Walk-In Lab location
- Simple blood draw — quick collection in four specialized tubes
- Get results — confidential results delivered within 2–5 days
FAQ
Is fasting required before the test? No, you can eat and drink normally before your blood draw.
How accurate is this test compared to the skin test? QuantiFERON TB Gold Plus has 94% sensitivity and 97% specificity, making it more accurate than traditional skin tests (Mayo Clinic 2025).
Will previous TB vaccination affect my results? No, this blood test is not affected by prior BCG vaccination, unlike skin tests that often show false positives.
What's the difference between latent and active TB? Latent TB means bacteria are dormant in your body without symptoms. Active TB causes illness with symptoms like cough, fever, and weight loss.
Can I order this test without a doctor's prescription? Yes, you can order directly through Walk-In Lab without needing a doctor's visit or prescription.
How quickly will I get my results? Results are typically available within 2–5 days of your blood draw.
More Details
What is the purpose of this test?
The QuantiFERON TB Gold Plus blood test detects infection with Mycobacterium tuberculosis, the bacteria that causes tuberculosis (TB). It measures your immune system's interferon-gamma response to TB-specific antigens from both CD4+ and CD8+ T cells (LabCorp 2025). This advanced test can distinguish between latent TB infection (dormant bacteria) and active TB disease, providing crucial information for treatment decisions.
Who would benefit from this test?
This test is particularly valuable for high-risk individuals including healthcare workers, immunocompromised patients, recent immigrants from TB-endemic areas, and anyone requiring TB screening for employment or immigration (CDC 2025). With an estimated 13 million Americans having latent TB infection, early detection is essential for preventing progression to active disease.
When should I order QuantiFERON TB Gold Plus?
Order this test if you've been exposed to TB, have risk factors for infection, need screening for work or school requirements, or experience TB symptoms like persistent cough, night sweats, unexplained weight loss, or fatigue (CDC 2025). It's also recommended for routine screening in high-risk populations and monitoring individuals with chronic conditions that increase TB susceptibility.
How do I interpret the results?
Negative
- What it means: No evidence of TB infection
- Typical action: No treatment needed; continue routine screening if high-risk
Positive
- What it means: TB infection likely present
- Typical action: Further evaluation needed; chest X-ray recommended
Indeterminate
- What it means: Test cannot be interpreted
- Typical action: Repeat testing or consider alternative diagnostic methods
A positive result doesn't automatically mean active TB disease—further testing helps determine if treatment is needed.
Disclaimer: Reference ranges may vary by laboratory. Listed ranges are general guidelines and may differ from those used by the performing lab. Always consult your healthcare provider for interpretation.
Pre-test preparation
No special preparation is required for this test. You don't need to fast or avoid any foods or medications. However, inform your healthcare provider about any immunosuppressive medications or recent illnesses, as these may affect test interpretation (LabCorp 2025). The blood sample must reach the laboratory within 14 hours of collection for accurate results.
How often should I get tested?
- Healthcare workers: Annually or per employer requirements
- High-risk individuals: Every 1–2 years or as recommended
- Recent TB exposure: 8–10 weeks after exposure
- Immunocompromised: Every 6–12 months
- General population: Only if symptoms or exposure occur
Why early detection matters
Early TB detection can prevent progression from latent to active disease, reduce transmission risk, and improve treatment outcomes. TB remains one of the leading infectious causes of death worldwide, making screening essential for public health (CDC 2025). Treating latent TB infection reduces the risk of developing active TB by up to 90% and helps prevent spread to family members and coworkers.
Related tests you may consider
Tetanus Titer Blood Test – Measures antibody levels against tetanus to assess immunity status or response to vaccination. Useful for confirming protection after vaccination or prior to certain medical procedures or travel.
Poliovirus 1 and 3 Antibody Immune Status Blood Test – Measures antibodies to poliovirus types 1 and 3 to assess immunity from past infection or vaccination, helping determine protective status against polio.
HIV Screening — Important for TB risk assessment since HIV significantly increases TB susceptibility and progression risk.
