Watermelon IgG Antibody [RAST], Qualitative — Deprecated
A blood test that looks for IgG antibodies to watermelon. This deprecated test generally indicates prior exposure and does not by itself diagnose a watermelon allergy.
["Watermelon-specific IgG usually reflects previous exposure rather than an active allergy."]
Key facts at a glance
- LOINC
- 21601-0
- Short code
- Deprecated Watermelon IgG RAST Ql
- Synonyms
- Deprecated Watermelon 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 watermelon proteins. RAST is an older laboratory method for detecting allergen-specific antibodies.
Why might I need this test?
It may have been used to assess immune exposure to watermelon or help evaluate a suspected food-related reaction. Food-specific IgG results generally do not show whether a person has an immediate allergy.
How is the test performed?
A blood sample is tested for antibodies that bind to watermelon allergens. The result is reported as positive or negative, and the test is now deprecated and may not be available.
How do I prepare for the test?
No special preparation is usually required for a blood antibody test. Follow any instructions provided by the ordering clinician or laboratory.
Reference range
Adult: 10-40 U/LN/A
No special preparation required. Avoid fatty meals before the test if possible.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
A positive result generally indicates that the immune system has produced IgG antibodies to watermelon, often because of previous exposure. This finding alone does not confirm a food allergy, especially when symptoms are not reproducible. If you have hives, swelling, wheezing, or other immediate symptoms after eating watermelon, discuss evaluation for IgE-mediated allergy with a clinician.
Short name
Watermelon IgG antibody test
Frequently asked questions
Does a positive result mean I am allergic to watermelon?
Why is this test marked as deprecated?
What should I do if I react after eating watermelon?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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