Egg White-Specific IgG Antibody, Qualitative — Radioallergosorbent Test (RAST; Deprecated)
A qualitative blood test that detects IgG antibodies to egg white using a legacy RAST method. It indicates exposure or sensitization, not necessarily egg allergy.
["A positive result shows egg-white-specific IgG antibodies, but it does not by itself diagnose an egg allergy."]
Key facts at a glance
- LOINC
- 21253-0
- Short code
- Deprecated Egg White IgG RAST Ql
- Synonyms
- Deprecated Egg White 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 qualitative test checks a blood sample for IgG antibodies directed against egg white. It uses the radioallergosorbent test (RAST) method, which is a legacy testing approach.
Why might I need this test?
It may be used to help evaluate prior exposure to egg or sensitization to egg proteins. Results must be interpreted with symptoms, dietary history, and other allergy testing because IgG antibodies can occur without a true allergy.
How is the test performed?
A blood sample is collected and tested in the laboratory for the presence of egg-white-specific IgG antibodies. The result is reported as positive or negative rather than as a specific concentration.
How do I prepare for the test?
No special preparation is usually required for the blood draw. Follow any instructions from the ordering clinician, particularly if additional allergy testing has been planned.
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 egg-white-specific IgG antibodies are present, which may reflect prior exposure or sensitization. It does not confirm that egg protein is causing symptoms, and a negative result does not completely exclude egg allergy. Your clinician will interpret the result alongside your history and other appropriate tests.
Short name
Egg White IgG Antibody (RAST)
Frequently asked questions
Does a positive result mean I am allergic to eggs?
What symptoms may prompt this test?
Why is this test listed 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