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Carrot-Specific IgG Antibody, Qualitative (RAST Method) — Deprecated

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

A legacy qualitative blood test for antibodies against carrot. A positive result indicates an immune response but does not by itself confirm a carrot allergy.

Quick summary

["This deprecated test detects carrot-specific IgG, which may reflect food exposure rather than a true allergy."]

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

Key facts at a glance

LOINC
21145-8
Short code
Deprecated Carrot IgG RAST Ql
Synonyms
Deprecated Carrot 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 is a qualitative test that looks for IgG antibodies directed against carrot in a blood sample. RAST refers to an older radioallergosorbent testing method, and this test has been marked as deprecated.

Why might I need this test?

It may have been used to evaluate an immune response to carrot or investigate a suspected food reaction. Because food-specific IgG testing does not reliably distinguish allergy from tolerance or prior exposure, results should be interpreted with your symptoms and medical history.

How is the test performed?

A blood sample is tested using the RAST method, and the result is reported as positive, negative, or otherwise not detected. The laboratory may use different testing methods if the original deprecated assay is unavailable.

How do I prepare for the test?

No special preparation is usually required, but follow any instructions provided by the ordering clinician or laboratory. Tell the clinician about carrot reactions, other food allergies, and any medications or supplements you use.

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

Carrot-Specific IgG (RAST)

Frequently asked questions

Does a positive carrot-specific IgG result mean I am allergic to carrots?
No. Carrot-specific IgG can occur in people who tolerate carrot and does not by itself establish a clinical allergy. Your reaction history and, when appropriate, allergy evaluation are more informative.
Is this test useful for diagnosing a food allergy?
Generally, food-specific IgG testing is not recommended as the main diagnostic test for food allergy. Diagnosis usually relies on the clinical history and, when needed, skin-prick testing or supervised food challenges.
Why is the test described as deprecated?
The original RAST-based test is an older assay that may no longer be routinely available or recommended. Ask your clinician whether a current allergy evaluation would be more appropriate for your symptoms.
  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