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White Pepper-Specific IgG Antibody, Qualitative (RAST) — Deprecated

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

A deprecated qualitative blood test for IgG antibodies directed against white pepper. Detected antibodies may reflect exposure but do not establish food allergy.

Quick summary

["This test can detect white pepper-specific IgG, but it is not a reliable test for diagnosing food allergy."]

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

Key facts at a glance

LOINC
21454-4
Short code
Deprecated White Pepper IgG RAST Ql
Synonyms
Deprecated White Pepper 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 laboratory test looks for IgG antibodies directed against white pepper in a blood-derived sample using a qualitative RAST-type method. The result generally reports whether the antibodies were detected. This test is deprecated and may not be available or recommended.

Why might I need this test?

It may have been used to evaluate an immune response after eating white pepper or investigating a suspected food-related reaction. It is not a standard test for confirming food allergy, and food-specific IgG testing is generally not recommended for that purpose.

How is the test performed?

A laboratory analyzes the submitted sample for antibodies that bind to white pepper. Because the result is qualitative, it reports detection or nondetection rather than a precise antibody concentration.

How do I prepare for the test?

No special preparation is usually specified for this test. Follow the laboratory's collection instructions and tell the clinician about food reactions, allergies, and medications; do not stop prescribed medicines unless your clinician advises 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

White pepper IgG antibody test

Frequently asked questions

Does a positive result mean I am allergic to white pepper?
No. White pepper-specific IgG can occur after exposure and is not considered a reliable marker of food allergy. Your clinician should interpret the result alongside your symptoms and other appropriate allergy evaluation.
What is the difference between IgG and IgE?
IgG and IgE are different types of antibodies. IgE is the antibody class most closely associated with immediate food-allergy reactions, while food-specific IgG testing does not reliably diagnose allergy.
Why is this test marked deprecated?
The test is considered outdated or no longer generally recommended for evaluating food allergy. Ask your clinician about a current clinical assessment and appropriate allergy testing if a food reaction remains a concern.
  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