Vanilla-Specific IgG Antibody, Radioallergosorbent Test (RAST) — Qualitative
A qualitative test that checks for IgG antibodies directed against vanilla. A positive result indicates an immune response but does not by itself confirm a vanilla allergy.
["This test detects vanilla-specific IgG antibodies, which may reflect previous exposure but do not necessarily mean you have an allergy."]
Key facts at a glance
- LOINC
- 21591-3
- Short code
- Deprecated Vanilla IgG RAST Ql
- Synonyms
- Deprecated Vanilla 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 laboratory test for IgG antibodies against vanilla. It may also be called a vanilla-specific IgG RAST test and appears to be a legacy or deprecated test name.
Why might I need this test?
It may be ordered to evaluate an immune response to vanilla, particularly after eating or drinking products containing it. Because IgG antibodies can develop after exposure without causing symptoms, this test should not be used alone to diagnose allergy.
How is the test performed?
A blood sample is analyzed using a radioallergosorbent or related laboratory method. The qualitative result is reported as detectable or not detectable rather than as a measured concentration.
How do I prepare for the test?
Fasting is usually not required for this type of blood test. Follow the preparation instructions provided by your healthcare professional or laboratory.
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.
Detectable vanilla-specific IgG may indicate previous exposure or an immune response to vanilla. It does not necessarily mean that the antibodies are causing symptoms or that you have a vanilla allergy. If this is an older or deprecated test, your clinician may recommend more current allergy testing based on your symptoms and medical history.
Short name
Vanilla-Specific IgG (RAST)
Frequently asked questions
Does a positive result mean I am allergic to vanilla?
Is this the same as an IgE allergy test?
What if the result is not detectable?
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