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Recombinant Wheat Tri-a 19-Specific IgE Antibody, Qualitative (RAST; Deprecated)

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

A legacy blood test that checks for IgE antibodies against the wheat protein tri-a 19, indicating possible wheat sensitization.

Quick summary

["A positive result suggests your immune system recognizes wheat tri-a 19, but it does not by itself confirm a wheat allergy."]

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

Key facts at a glance

LOINC
81986-2
Short code
Deprecated Wheat (rTri a) 19 IgE RAST Ql
Synonyms
Deprecated Wheat (rTri a) 19 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 IgE antibodies directed against recombinant wheat tri-a 19, a protein found in wheat. It is reported qualitatively, meaning the result is detected or not detected.

Why might I need this test?

It may be used to help evaluate a suspected wheat allergy, especially when reactions occur after eating wheat. Results are considered alongside your symptoms, medical history, exposure history, and other allergy tests.

How is the test performed?

A blood sample is tested using an immunoassay that detects IgE binding to wheat tri-a 19. This is a legacy RAST-type test and has been marked as deprecated, so the laboratory may offer an alternative component-specific IgE test.

How do I prepare for the test?

Fasting is generally not required for this blood test. Follow any instructions from the laboratory, and do not stop prescribed medicines without discussing them with your clinician.

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

Wheat Tri-a 19 IgE

Frequently asked questions

Does a positive result mean I have a wheat allergy?
Not necessarily. It shows that IgE directed against wheat tri-a 19 was detected, but an allergy is diagnosed by combining this result with symptoms and other clinical findings.
What if the result is not detected?
This means the test did not detect IgE against wheat tri-a 19. It does not completely exclude wheat allergy, including allergy to other wheat proteins.
Why is this test called deprecated?
It is a legacy testing method and may no longer be available. Your clinician can determine whether a current wheat IgE or component-specific allergy test would be more appropriate.
  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