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Tomato-Specific IgG Antibody (RAST), Qualitative

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

A blood test that looks for IgG antibodies to tomato and reports whether they are detected. It may indicate prior exposure but does not by itself diagnose food allergy.

Quick summary

["Detectable tomato-specific IgG suggests prior immune exposure to tomato but does not confirm a clinical food allergy."]

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

Key facts at a glance

LOINC
21568-1
Short code
Deprecated Tomato IgG RAST Ql
Synonyms
Deprecated Tomato 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 qualitative blood test checks for IgG antibodies directed against tomato. Antibodies are proteins made by the immune system after exposure to a substance.

Why might I need this test?

It may be used to evaluate possible sensitization to tomato or investigate symptoms that could be related to tomato exposure. Results must be considered with your symptoms, medical history, and other allergy testing.

How is the test performed?

A blood sample is collected and tested for tomato-specific IgG using a laboratory antibody assay. The result is reported as detected or not detected.

How do I prepare for the test?

No special preparation is usually required. Follow any instructions from your healthcare provider or laboratory, and tell the clinician if you have recently started or stopped allergy treatment.

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

Tomato-Specific IgG

Frequently asked questions

Does a positive result mean I am allergic to tomato?
No. Tomato-specific IgG can occur in people without a clinical allergy, so the result must be interpreted with symptoms and other medical findings.
What if tomato-specific IgG is not detected?
This means the test did not detect IgG antibodies to tomato. It does not completely rule out sensitivity or an allergy, particularly if exposure has been recent or limited.
Is this the same as testing for tomato allergy?
It can provide information about immune exposure, but it is not a stand-alone food-allergy diagnosis. If you have immediate symptoms such as hives, swelling, wheezing, or difficulty breathing, seek urgent medical care.
  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