Peanut-Specific IgE Antibody to Ara h 1, Serum — Qualitative (Deprecated RAST)
A blood test that detects IgE antibodies to Ara h 1, a peanut allergen. This older RAST formulation is deprecated in favor of current allergy testing.
["A positive result indicates sensitization to Ara h 1 but must be interpreted with symptoms and other allergy findings."]
Key facts at a glance
- LOINC
- 81990-4
- Short code
- Deprecated Peanut (rAra h) 1 IgE RAST Ql
- Synonyms
- Deprecated Peanut (rAra h) 1 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 looks for peanut-specific IgE antibodies directed against Ara h 1, a major peanut allergen. IgE is an immune-system antibody associated with allergic reactions, and this older RAST-based test is considered deprecated.
Why might I need this test?
A clinician may order this test when there is concern about a peanut allergy, especially after a possible reaction or before an oral food challenge. It may also be used to help assess the risk of a future reaction to peanut.
How is the test performed?
A blood sample is collected by inserting a needle into a vein. The laboratory measures Ara h 1-specific IgE in the serum, and the result may be reported qualitatively or according to the assay's current reporting scale.
How do I prepare for the test?
Fasting is generally not required, and blood allergy tests are usually not affected by antihistamines. Do not stop prescribed medicines or change your diet without guidance from your clinician. Because this RAST version is deprecated, confirm with the ordering clinician which current peanut allergy test will be used.
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.
Detectable Ara h 1-specific IgE indicates that the immune system has become sensitized to this peanut protein. A positive result does not by itself prove that a person will react to peanut or determine the severity of a possible reaction. Results should be interpreted with symptoms, exposure history, other allergy tests, and sometimes an oral food challenge.
Short name
Peanut Ara h 1-Specific IgE
Frequently asked questions
Does a positive result mean I am allergic to peanuts?
Is this the same as a peanut skin-prick test?
Why was this RAST test deprecated?
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.
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