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

Red Top Grass Allergy (IgE)

IgE to redtop grass pollen, a summer grass pollen, from a 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 test measures IgE antibodies to redtop grass pollen, a summer grass pollen. People often check it when hay fever lines up with the grass season. A positive result shows sensitization, which does not by itself mean allergy. No fasting or other prep is needed.

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

Who should take this test?

For adults who want to know whether redtop grass pollen may be part of their hay fever, often when sneezing, congestion, or itchy eyes follow the summer 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 redtop grass pollen, one piece of information an allergist or other healthcare provider reads alongside when and where your symptoms happen.

Redtop grass pollen-specific IgE (g9)
IgE is the antibody involved in allergic reactions. This marker is the amount of IgE in your blood that recognizes redtop grass pollen, reported in kU/L. A level above the lab’s reference range means sensitization, not necessarily allergy.
Why it’s measured: To see whether you are sensitized to redtop grass pollen, a summer grass pollen.

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

Your result is reported as an IgE level in kU/L and compared with the lab’s reference range. A level above the range shows sensitization.

  • 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

Share your result with an allergist or other healthcare provider, who reads it with when and where your symptoms happen.

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.

No. Sensitization means your body has made IgE to redtop grass pollen. An allergy means that exposure causes symptoms. Many people are sensitized without having symptoms, so a positive result alone does not mean you are allergic.

A negative result does not clear an allergy either. An allergist or other healthcare provider reads your result with what happens when you are exposed.

Redtop grass pollen is a summer grass pollen. 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.

It can. Grass pollens share similar proteins, so sensitization to one grass can come with sensitization to others. That is one reason an allergist may look at several grass results together.

Cross-⁠reaction in a blood test does not show which grass is behind your symptoms, or whether you will have symptoms at all.

Yes. Redtop grass pollen is one of the allergens in the Rocky Mountain states panel. 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.

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.