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Haddock-Specific IgG Antibodies, Qualitative — Radioallergosorbent Test (RAST) (Deprecated)

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

A deprecated qualitative test that detects IgG antibodies directed against haddock, a fish.

Quick summary

["A positive result shows an immune response to haddock but does not by itself confirm a food allergy."]

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

Key facts at a glance

LOINC
21319-9
Short code
Deprecated Haddock IgG RAST Ql
Synonyms
Deprecated Haddock IgG RAST Ql
Category
liver
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
10
Ref high
40
Critical range
— – 10000 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 IgG antibodies against haddock, a type of fish. It uses a radioallergosorbent test (RAST) method to provide a qualitative result. The test is deprecated and may no longer be routinely available.

Why might I need this test?

It may have been ordered to evaluate a possible immune response after eating haddock or another fish. Because it is an older test, a clinician may prefer current allergy testing when symptoms suggest a true fish allergy.

How is the test performed?

A laboratory sample is analyzed using the RAST method to determine whether haddock-specific IgG antibodies are detectable. The result is reported as positive or negative rather than as a measured concentration.

How do I prepare for the test?

Special preparation is generally not required for this type of antibody test, but the ordering laboratory should provide specific instructions. Do not stop medications or deliberately avoid food unless your clinician tells you to do so.

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

Haddock-Specific IgG RAST

Frequently asked questions

Does a positive result mean I am allergic to haddock?
Not necessarily. Detectable IgG antibodies can occur after exposure and are not, by themselves, a diagnosis of food allergy. Your clinician should interpret the result in the context of your symptoms and medical history.
Is this the same as testing for fish allergy?
Not always. RAST is commonly associated with allergen-specific IgE testing, while this deprecated slug specifically names IgG. If the ordering was for suspected allergy, confirm the exact test and a more current testing option with the clinician.
Why is this test described as deprecated?
It is an older assay that may have limited availability and can be confused with allergy testing that measures IgE. Current evaluation for suspected food allergy generally relies on the clinical history, appropriately selected IgE testing, and sometimes supervised food challenge.
  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