Peanut (Ara h 5)-Specific IgE, Serum — Radioallergosorbent Test (RAST), Qualitative
Detects IgE antibodies to the peanut component Ara h 5 to help assess possible peanut sensitization and allergy.
["A positive result indicates peanut sensitization, but allergy symptoms and other clinical findings are needed to diagnose an allergy."]
Key facts at a glance
- LOINC
- 87719-1
- Short code
- Deprecated Peanut (rAra h) 5 IgE RAST Ql
- Synonyms
- Deprecated Peanut (rAra h) 5 IgE RAST Ql
- 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
- 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 peanut-specific IgE antibodies directed against Ara h 5, a component found in peanut. The radioallergosorbent test, or RAST, is an older laboratory method used to detect allergen-specific IgE.
Why might I need this test?
This test may be used to evaluate suspected peanut allergy or sensitization, especially when symptoms have occurred after eating peanut. It may also help distinguish an allergy to a particular peanut component from other food allergies.
How is the test performed?
A blood sample is drawn and tested for IgE antibodies to peanut Ara h 5. Because this is a qualitative test, the laboratory generally reports the result as detected or not detected, or as positive or negative.
How do I prepare for the test?
No special preparation is usually required. Tell your clinician if you are taking antihistamines or other medicines that could affect allergy testing, and do not stop prescribed medicines without medical advice.
Reference range
Adult: 10-40 U/LN/A
No special preparation required. Avoid fatty meals before the test if possible.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Detected Ara h 5-specific IgE indicates that the immune system has reacted to this peanut component, a form of sensitization. This finding may support a peanut allergy, particularly when it matches a history of symptoms, but it does not by itself prove that every exposure will cause a reaction. Results should be interpreted by a clinician together with symptoms, other allergy tests, and, when appropriate, supervised food challenges.
Short name
Peanut Ara h 5 IgE
Frequently asked questions
Does a positive result mean I am allergic to peanuts?
What are Ara h 5-specific IgE antibodies?
Should I avoid peanuts if this test is positive?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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.
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Medically reviewed by WellAlly Editorial Team Last reviewed August 17, 2026. · Read our editorial policy