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Lysozyme-Specific IgE Antibody, Radioallergosorbent Test (RAST), Qualitative — Deprecated

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

A qualitative blood test for IgE antibodies to lysozyme, an allergen. This legacy RAST test is deprecated and may no longer be available.

Quick summary

["Detects lysozyme-specific IgE antibodies, which may support a diagnosis of lysozyme allergy."]

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

Key facts at a glance

LOINC
15826-1
Short code
Deprecated Lysozyme IgE RAST Ql
Synonyms
Deprecated Lysozyme IgE 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 IgE antibodies directed against lysozyme, a protein that can act as an allergen. It is a legacy radioallergosorbent test (RAST) and has been deprecated.

Why might I need this test?

It may have been used to evaluate a suspected allergic reaction to lysozyme, including reactions after exposure to egg whites or products containing lysozyme. Your clinician will interpret any result alongside your symptoms and exposure history.

How is the test performed?

A blood sample is collected, and the laboratory tests the serum for lysozyme-specific IgE antibodies. The result is generally reported as positive or negative.

How do I prepare for the test?

No special preparation is usually required, but follow your clinician or laboratory's instructions. Tell the clinician about any antihistamine use, as these medicines can sometimes affect allergy-test results.

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

Lysozyme-specific IgE (RAST), qualitative

Frequently asked questions

Does a positive result mean I am allergic to lysozyme?
Not necessarily. It shows that the immune system has produced IgE antibodies to lysozyme, so your clinician should interpret it with your symptoms and known exposures.
What is lysozyme?
Lysozyme is an antimicrobial enzyme found in substances such as egg whites. Some people can develop an allergic reaction to it.
Why is this test deprecated?
This legacy RAST method has been replaced by newer testing approaches and may not be available. Ask your clinician about an alternative specific-IgE test if lysozyme allergy is still being evaluated.
  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