A patient seated in the chair before a blood draw
In person

False Ragweed Allergy (IgE)

IgE antibodies to false ragweed pollen, measured from one blood draw.

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  • 2,000+ lab locations. Find one near you
  • Nothing due at the lab. FSA / HSA accepted
  • Ordered by a licensed clinician

At a glance

Collection
Blood draw
A standard blood draw at the lab.
Preparation
None
Nothing to do ahead of time. Water is fine.
Results
3 to 5 days
Typical turnaround after your visit.
Where
2,000+ lab locations
Nationwide, with nothing due at the lab.

About this test

This blood test checks for IgE sensitization to false ragweed pollen, a late summer to fall weed pollen. False ragweed is common in the West and Southwest. A positive result shows sensitization, which is not the same as an allergy. There is nothing to do ahead of your visit.

For adults 18 and older. Test availability varies by lab location.

Who should take this test?

For adults in the West and Southwest who want to check for sensitization to false ragweed pollen, often when hay fever follows the late summer to fall season.

Ask about this test

Not sure this is the right test?

AI-generated. For information only, not medical advice. Call 911 for an emergency.

What does this test measure?

The result shows your level of IgE to false ragweed pollen, one piece of information an allergist or other healthcare provider reads alongside when and where your symptoms happen.

False ragweed pollen-specific IgE (w4)
Specific IgE is an antibody the immune system can make against one allergen. This marker measures IgE that recognizes false ragweed pollen, a late summer to fall weed pollen. A level above the lab’s reference range shows sensitization, read with the timing of your symptoms.
Why it’s measured: Checks for IgE sensitization to false ragweed pollen when symptoms follow the late summer to fall season.

How it works

  1. Step 1

    Order online

    Check out here. A licensed clinician in your state reviews your order and sends it to the lab.

  2. Step 2

    Visit a lab

    Bring a photo ID to any of 2,000+ lab locations. No fasting needed, and nothing is due at the lab.

  3. Step 3

    Get your results

    Results post to your account, usually in 3 to 5 days, each number next to the lab’s reference range.

Find a lab near you

Choose from 2,000+ lab locations nationwide. Your order works at any of them.

What your results tell you

Results come back as an IgE level in kU/L, compared with the lab’s reference range. Above the range shows sensitization, not necessarily allergy.

  • Your number next to the lab’s reference range
  • Explained in plain language
  • A licensed clinician reviews your order and, if appropriate, orders the test.
  • A lab report you can download and share

An allergist or other healthcare provider reads this result with the timing of your symptoms and decides on any next steps.

Clinical-grade testing, from the comfort of home.

From the lab to your report, every step of our process meets the gold standard in medical testing.

  • CLIA-certified labs

    Every lab we partner with is certified under the Clinical Laboratory Improvement Amendments, meeting both state and federal standards with regular independent inspections.

  • We protect your health data

    We protect your health data with encryption and do not sell it. Some results must be reported to public health authorities by law. See our Privacy Notice.

  • Rigorous quality assurance

    All partner labs run regular internal quality checks, participate in proficiency testing, and comply with federal and state lab regulations.

  • Clinician-reviewed reports

    Results are reviewed by an independent, licensed clinician.

Questions

Common questions.

Anything else, our care team answers by phone, text, or email.

Not on its own. A positive result means your immune system has made IgE to false ragweed pollen, which is called sensitization. Many people who are sensitized have no symptoms when they are exposed.

A diagnosis of allergy is made by a healthcare provider who looks at your symptoms and history along with results like this one. A negative result also does not by itself mean you are not allergic.

False ragweed pollen is a late summer to fall weed pollen, common in the West and Southwest. Pollen seasons can shift with weather and location, so timing varies from year to year.

When your symptoms happen is one clue an allergist or other healthcare provider uses alongside a result like this. A positive result shows sensitization, not that this pollen is the cause of your symptoms.

Yes. False ragweed pollen is one of the allergens in the Southwest allergy evaluation. Each panel measures IgE to a set of allergens the lab groups together, in one draw.

Each result in a panel is read the same way: sensitization is not the same as allergy, and an allergist reads it with your history.

Both look for IgE sensitization. A skin test checks how your skin responds to a small amount of an allergen, while this test measures IgE to false ragweed pollen in a blood sample. In many cases the two are considered comparable.

A blood test may be preferred in some situations, such as a widespread skin condition or recent use of medicines that affect skin tests. Don’t stop or change any medicine without talking with your healthcare provider.

Lab tests are informational and don’t diagnose conditions on their own. Available to adults 18 and older; test availability varies by lab location. A licensed clinician reviews your order and, if appropriate, orders the test. All testing is performed at CLIA-certified laboratories. Not for emergencies: if you think you may be having a medical emergency, call 911.