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Chymopapain-Specific IgE (RAST), Qualitative — Deprecated

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

A qualitative blood test that detects IgE antibodies to chymopapain, an enzyme that can cause allergic reactions.

Quick summary

["A positive result suggests allergic sensitization to chymopapain but must be interpreted with your symptoms and exposure history."]

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

Key facts at a glance

LOINC
15640-6
Short code
Deprecated Chymopapain IgE RAST Ql
Synonyms
Deprecated Chymopapain 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 chymopapain-specific IgE antibodies in blood. IgE is an immune-system protein associated with allergic reactions, and RAST is an older laboratory method used to detect antibodies to particular allergens. This test has been deprecated and may not be readily available.

Why might I need this test?

It may be considered when a person has symptoms after exposure to chymopapain, an enzyme used in laboratory work and in some medicines and foods. Symptoms may include sneezing, wheezing, hives, swelling, or other signs of an allergic reaction.

How is the test performed?

A blood sample is tested for IgE directed against chymopapain. Because this is a qualitative test, the result is generally reported as positive or negative rather than as a measured concentration.

How do I prepare for the test?

No special preparation is usually required for a blood test, and fasting is generally unnecessary. Antihistamines or other allergy medicines may affect some testing methods, so tell the healthcare professional what you are taking and do not stop medication unless instructed.

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

Chymopapain-Specific IgE

Frequently asked questions

Does a positive result mean I will definitely have an allergic reaction?
No. It indicates sensitization and must be interpreted with your symptoms, timing, and exposure history. Your clinician may recommend allergy testing or other evaluation before making a diagnosis.
What is chymopapain?
Chymopapain is a proteolytic enzyme related to papain. It can occur in certain occupational settings and in some medicines or food-processing environments.
Why is this test marked as deprecated?
It is an older type of allergy test that has largely been replaced by other laboratory methods. Its results should still be interpreted by a qualified healthcare professional.
  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