Orange-Specific IgG Radioallergosorbent Test, Qualitative (Deprecated)
A qualitative blood test that looked for IgG antibodies to orange. This test is deprecated and should not be used alone to diagnose or rule out food allergy.
["A positive result shows an immune response to orange but does not by itself confirm a clinical orange allergy."]
Key facts at a glance
- LOINC
- 21432-0
- Short code
- Deprecated Orange IgG RAST Ql
- Synonyms
- Deprecated Orange IgG 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 is a qualitative radioallergosorbent test, or RAST, designed to detect IgG antibodies directed against orange. The test is listed as deprecated because IgG food-antibody results do not reliably distinguish harmless sensitization from true food allergy.
Why might I need this test?
It may appear in older records or have previously been used to evaluate possible reactions to orange. A clinician familiar with the symptoms and medical history is better able to determine whether any food-allergy testing is appropriate.
How is the test performed?
A blood sample is analyzed in the laboratory for orange-specific IgG antibodies, and the result is reported as positive or negative. A positive result indicates that antibodies were detected, not that an allergic reaction will occur.
How do I prepare for the test?
No special preparation is generally described for this test. Because it is deprecated, contact the ordering clinician or laboratory before repeating it and discuss newer, symptom-guided allergy evaluation options.
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 means orange-specific IgG antibodies are present, which can occur with exposure or sensitization and is not proof of a true allergy. Symptoms such as hives, swelling, vomiting, or breathing difficulty after eating orange require clinical assessment. Current evaluation generally emphasizes the reaction history and, when appropriate, testing for allergy-specific IgE rather than food-specific IgG.
Short name
Orange-specific IgG test
Frequently asked questions
Does a positive result mean I am allergic to orange?
Why is this test listed as deprecated?
What should I do if I had a reaction after eating orange?
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