---
title: "Is the Tuberculosis (TB) Blood Test worth it?"
type: answer
url: "https://www.test-well.com/answers/tuberculosis-blood-test"
product_url: "https://www.test-well.com/tests/tuberculosis-blood-test"
price_usd: 91.99
reviewed_at: 2026-07-23
---

# Is the Tuberculosis (TB) Blood Test worth it?

> 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.

## Worth it for

- 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

## Consider skipping if

- 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

## At-home vs in-lab

At-home collection is not offered for this test. 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 the results

| Result | Typical adult range | What an out-of-range value can mean |
| --- | --- | --- |
| 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

### Is the TB blood test accepted for immigration?

For your own preparation, yes - it is the same IGRA test type civil surgeons use. But the official I-693 exam must be performed by a USCIS-designated civil surgeon who orders testing under their own direction. Self-ordered results do not replace the exam; they tell you in advance what the exam will find, which is exactly what protects your timeline.

### TB blood test vs skin test - which should I get?

The blood test, almost always. It needs one visit instead of two, and it is not affected by the BCG vaccine - the skin test frequently reads falsely positive in BCG-vaccinated people, which describes most students and immigrants from TB-endemic countries. The CDC prefers IGRA testing for anyone BCG-vaccinated, and universities accept it universally.

### What does a positive TB blood test actually mean?

Exposure, not illness. A positive IGRA means your immune system has met TB bacteria before - true for about a quarter of the world's population. It cannot distinguish latent infection from active disease, so the next step is a chest X-ray. Latent TB is not contagious and is treatable with a 3-4 month antibiotic course; schools and employers work with documented latent TB routinely.

### How fast do I get TB test results for a school deadline?

Results arrive 3-5 business days after your draw, and you can usually walk into a Quest or Labcorp the same day you order - no appointment or US doctor needed. Most students clear a health hold within a week, end to end.

## Order

[Tuberculosis (TB) Blood Test](https://www.test-well.com/tests/tuberculosis-blood-test) — $91.99 + $6 lab processing fee, physician authorization included.

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Medically reviewed by Youmna DiStefano, MD (Medical Reviewer, TestWell); last reviewed 2026-07-23. Review policy: https://www.test-well.com/editorial-policy

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Prices are cash-pay, in USD, and include physician authorization; every order adds one flat $6 lab processing fee. Educational content is not a diagnosis — discuss results with a clinician.