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Qualitative IgG Radioallergosorbent (RAST) Test — Deprecated

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

An archived qualitative test that appears to detect IgG antibodies against selected antigens using a RAST-style immunoassay.

Quick summary

["A positive result means IgG to the tested antigen was detected, but it does not by itself diagnose an allergy or other disease."]

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

Key facts at a glance

LOINC
33304-7
Short code
Deprecated P notatum IgG RAST Ql
Synonyms
Deprecated P notatum 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 appears to be a deprecated qualitative laboratory test for antigen-specific IgG using a radioallergosorbent test, or RAST, format. The antigen descriptor is unclear, so the test is described generically.

Why might I need this test?

Historically, RAST-style testing was used to evaluate immune responses to selected allergens or other antigens. It has generally been superseded by newer, more standardized allergy testing methods.

How is the test performed?

The laboratory combines the patient's sample with selected antigens and determines whether antigen-specific IgG is detected. The result is reported as positive, negative, or possibly another qualitative interpretation.

How do I prepare for the test?

No special preparation can be confirmed from the test information provided. Follow the laboratory's instructions, including any fasting or medication guidance, and tell the clinician if you have a known allergy or recent exposure to the tested antigen.

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

Qualitative IgG RAST

Frequently asked questions

Does a positive IgG RAST result mean I am allergic?
Not necessarily. Detected IgG may indicate exposure or immune recognition, while immediate allergic reactions are usually associated with IgE and must be interpreted with symptoms and other appropriate testing.
Why is this test described as deprecated?
It is an older testing format that has generally been replaced by newer laboratory methods. A clinician can help determine whether more current testing is appropriate.
What should I do with the result?
Review it with the ordering clinician, especially if you have symptoms or a history of allergy. The result should be considered together with your history and any newer allergy tests.
  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