Apple-Specific IgG Radioallergosorbent Test (RAST), Qualitative — Deprecated
A qualitative serum test for IgG antibodies directed against apple proteins. This legacy RAST-based test is deprecated and may not be available.
["A positive result shows apple-specific IgG antibodies, but it does not by itself confirm a true apple allergy."]
Key facts at a glance
- LOINC
- 21072-4
- Short code
- Deprecated Apple IgG RAST Ql
- Synonyms
- Deprecated Apple 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 test looks for IgG antibodies that react with proteins from apples in a blood sample. It uses a radioallergosorbent testing method, which is sometimes called RAST. The test is considered deprecated and may no longer be offered.
Why might I need this test?
It may have been used to evaluate an apparent food reaction to apples or as part of a food-antibody panel. Food-specific IgG results are generally considered markers of exposure or sensitization rather than reliable evidence of allergy.
How is the test performed?
Laboratory personnel expose serum to apple allergen and use a labeled anti-human IgG reagent to detect any apple-specific IgG that binds. The result is reported as positive or negative rather than as a measured concentration.
How do I prepare for the test?
No special preparation is usually required for a blood draw. Because this is a deprecated test, contact the laboratory before ordering it to confirm availability and the required specimen.
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 that apple-specific IgG antibodies are present, which can occur after exposure and does not necessarily mean clinically significant allergy. A negative result does not completely exclude apple sensitization or allergy. Results should be interpreted alongside symptoms, medical history, and other allergy testing when clinically appropriate.
Short name
Apple-Specific IgG (RAST)
Frequently asked questions
Does a positive apple-specific IgG result mean I am allergic to apples?
What is a RAST test?
Why is this test listed as 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