Is a Tuberculosis (TB) Blood Test worth it?
What it costs, whether to test at home or at Quest or Labcorp, and how to read your results.
Medically reviewed by Youmna DiStefano, MD — updated July 2026
The short answer
Yes when someone requires TB documentation from you - a university, employer, or your own preparation ahead of an immigration medical exam - or after a known exposure. The QuantiFERON blood test needs one visit, is not skewed by childhood BCG vaccination, and produces the CLIA-certified report institutions accept.
Who should order it (and who can wait)
Worth it if you...
- •International students clearing a university health hold (most US schools accept outside IGRA results)
- •Healthcare workers, teachers, and other jobs with TB screening requirements
- •Green-card applicants pre-screening before the civil-surgeon exam (a positive found early is a plan; found at the exam, it is a delay)
- •Anyone BCG-vaccinated whose old skin test read 'positive' and wants their true status on record
- •Known or suspected exposure to someone with active TB
You can probably wait if you...
- •You need the OFFICIAL I-693 immigration medical - only a USCIS civil surgeon can perform that exam; this test is preparation, not a substitute
- •You have symptoms of active TB (weeks of cough, night sweats, weight loss, coughing blood) - see a provider promptly; screening tests are for people without symptoms
We would rather you order the right test than the most expensive one.
At-home vs Quest vs Labcorp
The most common question we get. The short version: the lab and the result are the same - you are choosing where the blood is drawn.
Walk into a lab
Get drawn at any Quest or Labcorp location - thousands nationwide, often same-day. Best for speed and lowest cost.
At-home draw
Not recommended for this test - it needs a lab-based collection to be accurate.
Same result
Whichever you pick, it is run on the same CLIA-certified analyzers with the same reference ranges.
This is a walk-in venous draw at Quest or Labcorp. QuantiFERON samples must be processed within about 16 hours of collection in special tubes, which is why it is not a mail-in kit and why we route it through lab locations that handle it daily. No fasting or preparation - walk in any time.
How to read your results
The markers that matter most and what an out-of-range value can mean. Reference ranges vary by lab, age, and sex.
| Marker | Typical range | What it means |
|---|---|---|
| QuantiFERON-TB Gold Plus (IGRA) | Negative | Negative means no immune memory of TB bacteria - the result schools and employers are looking for. Positive means exposure at some point (roughly 1 in 4 people worldwide), NOT active disease; the next step is a chest X-ray to rule out active TB, and latent TB is treatable with a short antibiotic course. |
Frequently asked questions
Ready to order your Tuberculosis (TB) Blood Test?
$91.99, physician-authorized, results in 3–5 business days. No insurance or doctor's visit required.
About this guide
Reviewed July 23, 2026. This is general health information, not medical advice, diagnosis, or treatment. Reference ranges vary by laboratory, age, sex, and clinical context - always interpret results with a qualified healthcare provider. Lab analysis is performed at CLIA-certified Quest Diagnostics and Labcorp facilities.