Oat-Specific IgG, Radioallergosorbent (RAST) Test, Qualitative — Deprecated
A legacy blood test for oat-specific IgG. It is not routinely used to diagnose food allergy because IgG may reflect exposure rather than harmful allergy.
["This deprecated test cannot reliably determine whether you have a clinically significant oat allergy."]
Key facts at a glance
- LOINC
- 21426-2
- Short code
- Deprecated Oat IgG RAST Ql
- Synonyms
- Deprecated Oat 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 blood test that looks for IgG antibodies directed against oat proteins. The test has been deprecated and is not routinely recommended for diagnosing food allergy.
Why might I need this test?
It may appear in older records or be ordered in a specialized evaluation. Today, food-allergy assessment usually relies on the clinical history and, when appropriate, skin-prick testing or allergen-specific IgE testing.
How is the test performed?
A blood sample is examined with a laboratory method designed to detect oat-reactive IgG. Because this assay is deprecated, the specimen and testing method should be confirmed with the laboratory.
How do I prepare for the test?
A blood draw generally requires no special preparation, but you should follow the laboratory's instructions. Tell your clinician about food reactions, allergies, and medications; do not stop any medication unless instructed.
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 shows that oat-specific IgG antibodies are present, which may reflect previous exposure or tolerance rather than an allergy. A negative result does not completely exclude oat allergy. Results should be interpreted alongside symptoms and other appropriate allergy testing.
Short name
Deprecated Oat IgG Test
Frequently asked questions
Does a positive oat IgG result mean I am allergic to oats?
What test is generally used to evaluate a possible food allergy?
Why is this test marked 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.
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Medically reviewed by WellAlly Editorial Team Last reviewed August 17, 2026. · Read our editorial policy