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Cocksfoot-Specific IgE, Qualitative (Radioallergosorbent Test [RAST])

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

A legacy qualitative test for IgE antibodies to cock's-foot pollen. A positive result can suggest allergy sensitization but does not confirm symptoms.

Quick summary

["This blood test checks for an immune response to cock's-foot pollen, which can cause seasonal allergy symptoms."]

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

Key facts at a glance

LOINC
15746-1
Short code
Deprecated Cocksfoot IgE RAST Ql
Synonyms
Deprecated Cocksfoot IgE RAST Ql
Category
liver
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
10
Ref high
40
Critical range
— – 10000 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 test looks for IgE antibodies directed against cock's-foot grass pollen, a common source of seasonal allergy symptoms. RAST is an older name for certain allergen-specific IgE blood tests, and this form of the test is considered deprecated in many laboratories.

Why might I need this test?

It may be used to evaluate possible grass-pollen allergy, particularly when symptoms such as sneezing, runny nose, or itchy eyes occur during grass-pollen seasons. Results may also help guide allergy management.

How is the test performed?

A blood sample is collected and tested in the laboratory for antibodies to cock's-foot pollen. The result is reported as positive or negative. Many laboratories now offer newer allergen-specific IgE assays rather than RAST.

How do I prepare for the test?

Fasting is generally not required. Tell your clinician about any allergy medicines you take, because antihistamines and certain other treatments can affect the result; 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.

◆Associated findings1

Short name

Cocksfoot-specific IgE

Frequently asked questions

What does a positive result mean?
It means your immune system reacts to cock's-foot pollen, which is consistent with sensitization. Your clinician can compare this finding with your symptoms to assess whether it is clinically relevant.
Does a positive result confirm a pollen allergy?
Not always. A positive result shows sensitization, but pollen may not be the cause of your symptoms and false-positive results can occur.
How is this different from a skin-prick test?
This test uses a blood sample to detect allergen-specific IgE, while a skin-prick test measures an immediate skin reaction. Blood testing may be considered when skin testing is difficult or not appropriate.
  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