Whitefish-Specific Immunoglobulin G (IgG), Radioallergosorbent Test (RAST), Qualitative (Deprecated)
A qualitative, deprecated test for whitefish-specific IgG that can help assess prior exposure, but it does not by itself diagnose an IgE-mediated fish allergy.
["This blood test looks for whitefish-specific IgG, which may reflect previous exposure rather than a true allergy."]
Key facts at a glance
- LOINC
- 21605-1
- Short code
- Deprecated Whitefish IgG RAST Ql
- Synonyms
- Deprecated Whitefish 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 uses the radioallergosorbent technique (RAST) to look for IgG antibodies directed against whitefish. It reports a qualitative result and is marked as deprecated, meaning it may no longer be routinely offered or may have been replaced by another method.
Why might I need this test?
Whitefish-specific IgG may be measured to help evaluate a reported reaction or document previous exposure to whitefish. It can also support the assessment of the immune response to this food.
How is the test performed?
A blood sample is collected, and the laboratory uses a radioallergosorbent method to detect whitefish-specific IgG binding. The result is reported as positive, negative, or another laboratory-defined qualitative interpretation.
How do I prepare for the test?
No special preparation is usually required, but tell your clinician about any fish allergy, recent whitefish exposure, symptoms, and medicines you are taking. Because this test is deprecated, confirm with the laboratory that it is still available.
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 whitefish-specific IgG was detected and may reflect previous exposure or a non-IgE immune response. A negative result does not completely exclude prior exposure or allergy, and IgG results should not be interpreted alone as proof of a clinically significant whitefish allergy. If an immediate allergy is suspected, evaluation with a current allergy test and clinical history is generally needed.
Short name
Whitefish IgG RAST (Qualitative)
Frequently asked questions
Does a positive result mean I am allergic to whitefish?
Is this the same as a whitefish IgE allergy test?
Why is the test described 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