English Walnut (Juglans regia) rJug r 3-Specific IgE Antibody, Qualitative (Deprecated)
A qualitative blood test that detects IgE antibodies directed against the English walnut allergen rJug r 3.
["A positive result suggests an immune sensitization to English walnut but must be interpreted with symptoms and allergy history."]
Key facts at a glance
- LOINC
- 82545-5
- Short code
- Deprecated English walnut (rJug r) 3 IgE RAST Ql
- Synonyms
- Deprecated English walnut (rJug r) 3 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 test looks for IgE antibodies specific to rJug r 3, a protein found in English walnuts. A positive result indicates that the immune system has recognized this walnut protein as a potential allergen.
Why might I need this test?
It may be used to help evaluate a suspected English walnut allergy, especially after an unexplained reaction involving walnuts. Results are considered alongside your symptoms, exposure history, and other allergy tests.
How is the test performed?
A laboratory analyzes a blood sample for antibodies against the rJug r 3 walnut protein. This is a qualitative test, so the result is reported as positive or negative.
How do I prepare for the test?
No special preparation is usually required. Tell your clinician about any recent allergic reaction, other food allergies, medicines, and whether you have recently stopped an allergy treatment.
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.
A positive result indicates IgE sensitization to the rJug r 3 English walnut protein and may support a diagnosis of walnut allergy when it matches the clinical history. It does not by itself prove that a reaction will occur or identify the severity of a future reaction. A negative result does not completely exclude walnut allergy because other walnut proteins or non-IgE reactions may be responsible.
Short name
English Walnut rJug r 3 IgE
Frequently asked questions
Does a positive result mean I am allergic to English walnuts?
What if the test is negative but I react after eating walnuts?
Why is this test labeled 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