Peach-Specific IgG Antibodies — Radioallergosorbent Test (RAST), Qualitative (Deprecated)
A qualitative blood test that detects IgG antibodies directed against peach proteins. It is not routinely used to diagnose peach allergy.
["A positive result shows a peach-specific IgG response but does not by itself mean you have a peach allergy."]
Key facts at a glance
- LOINC
- 21446-0
- Short code
- Deprecated Peach IgG RAST Ql
- Synonyms
- Deprecated Peach 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 laboratory test looks for IgG antibodies your immune system has made in response to peach proteins. RAST is an older laboratory method for detecting allergen-specific antibodies, and food-specific IgG testing is now considered deprecated for diagnosing food allergy.
Why might I need this test?
It may have been ordered to evaluate a reported reaction to peaches or as part of an older food-antibody panel. Because IgG results can occur without true allergy, your clinician should interpret them alongside your symptoms, medical history, and any allergy testing.
How is the test performed?
A blood sample is collected and tested with peach antigen using a RAST or similar laboratory method. The result is reported qualitatively, generally as positive or negative, indicating whether detectable peach-specific IgG was found.
How do I prepare for the test?
No special preparation or fasting is usually required for this blood test. Follow any instructions provided by the ordering clinician or laboratory, especially if you have recently eaten peaches or started a new medication.
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 peach-specific IgG antibodies are detectable, which may reflect previous exposure or an immune response but does not prove a clinically significant allergy. A negative result does not completely rule out peach allergy, particularly an immediate reaction. If you have symptoms after eating peaches, discuss evaluation with an allergist rather than relying on this IgG test alone.
Short name
Peach-Specific IgG (RAST)
Frequently asked questions
Does a positive result mean I am allergic to peaches?
Can this test diagnose a peach allergy?
Why is this test marked 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