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Grass Allergen Mix 1 IgE, Serum — Radioallergosorbent Test (RAST)

Published: August 9, 2026Updated: August 17, 2026

A blood test that measures IgE antibodies to a mixture of grass allergens, helping evaluate possible grass-pollen allergy.

Quick summary

["Elevated IgE suggests an immune reaction to grass allergens, but it must be interpreted alongside your symptoms."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
24478-0
Short code
Grass Allerg Mix1 IgE RAST
Synonyms
Grass Allerg Mix1 IgE RAST
Category
liver
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
10
Ref high
40
Critical range
— – 500 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
multidisk
CPT
84484
SNOMED
302774002
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What is this test?

This blood test measures allergen-specific IgE antibodies against a mixture of common grass pollens. IgE is a type of immune protein that can form in response to an allergen.

Why might I need this test?

Your clinician may order it when you have sneezing, congestion, itchy or watery eyes, wheezing, or other symptoms associated with exposure to grass. It can help identify whether grass allergens are a possible trigger.

How is the test performed?

A blood sample is collected and tested in the laboratory for IgE antibodies to the grass allergen mixture. The test is sometimes described as a RAST, although many laboratories use other immunoassay methods.

How do I prepare for the test?

Fasting is usually not required. Tell your clinician about any allergy medicines you take, because antihistamines and some other treatments can affect allergy testing; do not stop prescribed medication without advice.

Reference range

Adult: 10-40 U/LN/A

Specimen: serum

No special preparation required. Avoid fatty meals before the test if possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Detectable or elevated grass-specific IgE indicates immune sensitization to one or more allergens in the mixture. This may support grass-pollen allergy when it matches your symptoms and exposure history, but a positive result alone does not confirm a clinically important allergy or identify the specific grass involved.

Short name

Grass Allergen Mix 1 IgE

Frequently asked questions

Does a positive result mean I am allergic to grass?
It indicates that your immune system has produced IgE antibodies to at least one grass allergen in the mixture. Your clinician must interpret this together with your symptoms to determine whether the result is clinically significant.
Can this test tell me exactly which grass causes my symptoms?
Usually not. This test uses a mixture of grass allergens, so it can show sensitization to the group but may not identify a particular grass species.
Do I need to avoid grass before the test?
No special avoidance is generally required. Recent exposure does not need to be arranged, but tell your clinician about your symptoms and when they occur.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 17, 2026. · Read our editorial policy