Decapod Crustacean-Specific IgG Antibodies, Qualitative
Detects IgG antibodies to shrimp, lobster, crab, and related decapod crustaceans. Results are reported as negative or positive.
["A positive result shows prior immune exposure to decapod crustaceans but does not by itself diagnose a food allergy."]
Key facts at a glance
- LOINC
- 100394-6
- Short code
- Decapod crustaceans IgG Qn
- Synonyms
- Decapod crustaceans IgG Qn
- Category
- liver
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 0
- Ref high
- 5
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 82378
- SNOMED
- 394995008
- 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 test detects IgG antibodies directed against decapod crustaceans, such as shrimp, lobster, crab, and crayfish. A positive result indicates that your immune system has recognized proteins from these foods.
Why might I need this test?
It may be ordered to assess immune exposure to crustaceans, particularly when a history of symptoms after eating seafood is being evaluated. It can also help distinguish an immune response from symptoms caused by other food-related conditions.
How is the test performed?
A laboratory analyzes the submitted sample for crustacean-specific IgG antibodies. Because the method may vary by laboratory, the sample type and testing procedure should be confirmed with the ordering clinician.
How do I prepare for the test?
Follow the laboratory's instructions regarding sample collection and timing. Tell the care team if you recently ate crustaceans or other shellfish, because recent exposure may affect the result.
Reference range
Non-smokers: <2.5 ng/mL; Smokers: <5.0 ng/mLN/A
No special preparation required. For PSA, avoid sexual activity for 24-48 hours before the test.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
A positive result indicates detectable IgG antibody to decapod crustaceans and is consistent with previous exposure or immune recognition. IgG results do not confirm an immediate IgE-mediated allergy, so they must be interpreted alongside symptoms, medical history, and other allergy testing. A negative result does not completely exclude sensitivity or an allergy.
Short name
Crustacean-Specific IgG Antibody Test
Frequently asked questions
Does a positive result mean I am allergic to shrimp or lobster?
What foods are included in the decapod crustacean group?
What if I have eaten crustaceans recently?
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 16, 2026. · Read our editorial policy