Skip to content

Black Pepper–Specific IgG Antibody, Qualitative (Radioallergosorbent Test)

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

A qualitative blood test that detects IgG antibodies directed against black pepper using the RAST method.

Quick summary

["A detectable result shows black pepper–specific IgG antibodies but does not by itself confirm a food allergy."]

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

Key facts at a glance

LOINC
21449-4
Short code
Deprecated Black Pepper IgG RAST Ql
Synonyms
Deprecated Black Pepper IgG RAST Ql
Category
liver
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
10
Ref high
40
Critical range
— – 10000 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 blood test checks for IgG antibodies that your immune system has made in response to black pepper. It is a qualitative test, meaning it reports detectable or not detectable rather than providing a numeric antibody level. This is a deprecated testing method and is not routinely recommended for diagnosing food allergy.

Why might I need this test?

It may have been ordered to evaluate an immune response after eating black pepper or as part of a broader food-antibody panel. Results should be interpreted alongside your symptoms, exposure history, and other allergy testing.

How is the test performed?

A blood sample is tested using the radioallergosorbent technique, commonly called RAST. The laboratory checks whether black pepper–specific IgG antibodies can be detected in the sample.

How do I prepare for the test?

No special preparation is usually required. Tell your clinician if you have recently eaten black pepper, recently started medicines, or have had an allergic reaction, because these details may affect interpretation.

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

Black pepper IgG antibody (RAST)

Frequently asked questions

Does a positive result mean I am allergic to black pepper?
No. IgG antibodies can occur with exposure and do not by themselves establish a clinical food allergy. Your clinician should interpret the result with your symptoms and other test findings.
Is this the same as a black pepper IgE test?
No. This test detects black pepper–specific IgG, whereas a food-specific IgE test evaluates the antibody type more closely associated with immediate allergic reactions.
Why is this test described as deprecated?
The RAST-based IgG food-antibody approach is a legacy testing method with limited clinical usefulness. Current food-allergy evaluation relies primarily on clinical history and, when appropriate, skin-prick or food-specific IgE testing.
  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