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Catfish-Specific IgG Antibody, Qualitative — Radioallergosorbent Test (RAST; Deprecated)

Published: August 9, 2026Updated: August 17, 2026

A qualitative blood test that detects antibodies directed against catfish proteins. It may indicate exposure or sensitization but does not by itself diagnose food allergy.

Quick summary

["A positive result suggests prior exposure to catfish, but it does not confirm an immediate food allergy."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
33283-3
Short code
Deprecated Catfish IgG RAST Ql
Synonyms
Deprecated Catfish 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 looks for catfish-specific IgG antibodies in a blood sample. RAST is a term historically associated with radioallergosorbent allergy testing, and this test code is marked as deprecated.

Why might I need this test?

It may be used to assess whether your immune system has reacted to proteins found in catfish, particularly when evaluating a suspected food-related reaction. Your clinician will interpret it alongside your symptoms, medical history, and other allergy tests.

How is the test performed?

A blood sample is collected and examined for antibodies that bind to catfish proteins. The result is reported as positive, negative, or not detected.

How do I prepare for the test?

Fasting is usually not required for this blood test. Follow your clinician's instructions and tell the laboratory if you have recently eaten catfish or received biologic treatments, because these may affect interpretation.

Reference range

Adult: 10-40 U/LN/A

Specimen: serum

No special preparation required. Avoid fatty meals before the test if possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Catfish-Specific IgG

Frequently asked questions

Does a positive result mean I am allergic to catfish?
Not necessarily. It indicates that catfish-specific IgG antibodies are detectable, which can reflect exposure or sensitization. Your clinician must interpret the result in the context of your symptoms and other allergy testing.
How is this different from a catfish-specific IgE test?
IgG and IgE are different antibody classes. IgE is more closely associated with immediate allergic reactions, while IgG more often reflects exposure or immune recognition and does not establish allergy by itself.
Why is this test marked as deprecated?
The test code is no longer the preferred choice for evaluating suspected food allergy. Your clinician may recommend a current allergy panel, a specific IgE test, or skin-prick testing instead.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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