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Sweet Potato-Specific IgG Antibody (RAST), Qualitative (Deprecated)

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

A qualitative blood test for IgG antibodies directed against sweet potato. This deprecated test indicates prior exposure but does not diagnose sweet potato allergy.

Quick summary

["A positive result shows sweet potato-specific IgG, not necessarily a clinical allergy."]

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

Key facts at a glance

LOINC
21548-3
Short code
Deprecated Sweet potato IgG RAST Ql
Synonyms
Deprecated Sweet potato 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 test looks for IgG antibodies to sweet potato in a blood sample. IgG antibodies can develop after exposure to a food, but they do not by themselves show that the food causes an allergic reaction. This test has been deprecated and is not routinely used to diagnose food allergy.

Why might I need this test?

It may have been ordered historically to evaluate possible food-related symptoms or document an immune response to sweet potato. Because food-specific IgG results do not reliably predict allergy, a clinician may instead use the medical history, symptom evaluation, and appropriately selected allergy testing.

How is the test performed?

A blood sample is analyzed in a laboratory for antibodies that bind to sweet potato antigens. The result is reported as positive, negative, or another qualitative interpretation, depending on the laboratory method.

How do I prepare for the test?

No special preparation is usually required for a blood draw. Follow the laboratory's instructions and tell the healthcare provider about any symptoms, food reactions, medications, and recent exposure to sweet potato.

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

Sweet potato IgG antibody test

Frequently asked questions

Does a positive sweet potato IgG result mean I am allergic?
No. Sweet potato-specific IgG can occur in people who tolerate the food and is not considered a reliable marker of food allergy. Symptoms and medical history are more useful for evaluating a suspected reaction.
What symptoms can suggest a sweet potato reaction?
Possible reactions may include hives, swelling, wheezing, vomiting, abdominal pain, or other symptoms occurring after eating sweet potato. Severe breathing difficulty, faintness, or widespread swelling requires urgent medical attention.
What test is used if sweet potato allergy is suspected?
A clinician may consider skin-prick testing or serum sweet potato-specific IgE testing when the history suggests an immediate allergy. These tests should be interpreted alongside symptoms because positive results can sometimes reflect sensitization without clinical allergy.
  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