Perch-Specific IgG Antibody, Radioallergosorbent Test (RAST) — Qualitative (Deprecated)
A qualitative test for antibodies against perch, a fish. This deprecated test is not generally used to diagnose food allergy.
["A result does not by itself confirm a perch allergy, and this older IgG test is not usually recommended."]
Key facts at a glance
- LOINC
- 33305-4
- Short code
- Deprecated Perch IgG RAST Ql
- Synonyms
- Deprecated Perch 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 directed against perch, a type of fish. The RAST method is a laboratory technique used to detect these antibodies, and a qualitative result is reported as positive or negative.
Why might I need this test?
Perch-specific IgG testing was historically available for evaluating possible reactions to fish. It is now considered deprecated because a positive result reflects prior exposure or sensitization and does not reliably indicate a true food allergy.
How is the test performed?
The laboratory combines the patient's sample with perch-derived material and uses the RAST method to determine whether perch-specific IgG is detectable. The final result is qualitative rather than a measurement used to assess reaction severity.
How do I prepare for the test?
No special preparation is usually required, but follow any instructions provided by the healthcare professional or laboratory. Tell the clinician if you have recently eaten fish or experienced symptoms after eating perch.
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 means that perch-specific IgG antibodies were detected, which may occur after previous exposure to perch. This finding alone does not diagnose allergy, predict the severity of a reaction, or substitute for a clinical evaluation. Because this test is deprecated, discuss the result with a healthcare professional who can recommend more appropriate allergy testing when indicated.
Short name
Perch-specific IgG (RAST)
Frequently asked questions
Does a positive result mean I am allergic to perch?
Why is this test called deprecated?
What should I do if the result is positive?
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