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Peanut Ara h 8 IgE Antibody, Serum — RAST, Qualitative

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

A blood test that detects IgE antibodies directed against Ara h 8, a peanut storage protein, to help assess possible peanut sensitization.

Quick summary

["A detectable result can indicate an immune response to the peanut protein Ara h 8, but it must be interpreted with your allergy history."]

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

Key facts at a glance

LOINC
81982-1
Short code
Deprecated Peanut (rAra h) 8 IgE RAST Ql
Synonyms
Deprecated Peanut (rAra h) 8 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 qualitative blood test measures allergen-specific IgE antibodies against Ara h 8, one of the storage proteins found in peanuts. It is sometimes described as a component-specific peanut IgE or RAST test.

Why might I need this test?

Your clinician may order this test when you have a history of reactions after eating peanuts. It can help determine whether your immune system recognizes Ara h 8 as an allergen and guide evaluation alongside your symptoms and other allergy testing.

How is the test performed?

A blood sample is drawn and tested for Ara h 8-specific IgE using a RAST-type laboratory method. The result is generally reported qualitatively, such as detected or not detected, although laboratory reporting may vary.

How do I prepare for the test?

Fasting is usually not required, and you do not need to eat peanuts for this test. Tell your clinician about medicines, recent biologic treatments, and other immune conditions, and do not stop any medication without medical 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

Peanut Ara h 8 IgE (RAST), Qualitative

Frequently asked questions

Does a positive result mean I have a peanut allergy?
It indicates that your immune system has produced IgE antibodies to Ara h 8, but it does not by itself prove that you will have symptoms when eating peanuts. Your clinician should interpret it with your reaction history and other findings.
Do I need to eat peanuts before this test?
No. This test measures antibodies in a blood sample and does not require deliberate peanut exposure. Eating peanuts shortly before the test is not usually necessary, but follow your clinician's specific instructions.
How is this different from a peanut skin-prick test?
A skin-prick test evaluates an immediate allergic response in the skin, while this blood test detects Ara h 8-specific IgE in the laboratory. The tests provide different information and may be interpreted together when 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