Understanding Lab Tests for Shellfish Allergy
Written by Private MD Labs Medical Writing Team • Last Updated: September 8, 2025
Shellfish allergy is one of the most common food allergies in adults, caused by an abnormal immune response to proteins found in various marine shellfish. Unlike other food allergies, shellfish allergy often develops in adulthood and tends to be lifelong. Accurate diagnosis through specialized blood tests is essential for proper management and avoiding potentially life-threatening reactions.
Top Recommended Test
Allergy-Shellfish Panel
This comprehensive panel tests for allergic reactions to multiple shellfish including clams, crab, lobster, and shrimp by measuring specific biomarkers. It can detect immune system responses that cause symptoms ranging from mild hives and itching to severe anaphylaxis, making it an essential diagnostic tool for identifying specific shellfish triggers.
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How Blood Tests Diagnose Shellfish Allergy
Blood tests for shellfish allergy measure specific antibodies (IgE and IgG4) that the immune system produces in response to shellfish proteins. These tests can identify which specific types of shellfish trigger allergic reactions, helping patients and healthcare providers develop appropriate avoidance strategies and emergency action plans.
Other Relevant Tests
Food Allergen Profile, IgE With Component Reflexes
This advanced test measures IgE antibodies specific to scallops and shrimp, providing detailed information about allergic responses to these common shellfish. Elevated IgE levels indicate true allergic reactions that can cause symptoms including hives, vomiting, diarrhea, and severe breathing difficulties.
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IgG4 Food Panel III
This test measures IgG4 antibodies to shrimp proteins, helping identify immune responses that can cause reactions ranging from mild symptoms like hives and itching to severe anaphylaxis. IgG4 testing provides additional insight into the body's immune response to shellfish proteins.
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IgG4 Food Panel IV
This panel tests for IgG4 antibodies to clams and lobster, two common shellfish allergens. It helps identify abnormal immune responses to proteins in these marine animals, which can cause symptoms ranging from mild to severe allergic reactions.
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IgG4 Food Panel VI
This test measures IgG4 antibodies specific to crab proteins. Elevated levels can indicate a shellfish allergy that may cause symptoms including hives, nausea, diarrhea, and in severe cases, life-threatening anaphylaxis.
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Understanding Your Test Results
Positive results on shellfish allergy tests indicate that your immune system has developed antibodies against specific shellfish proteins. The severity of test results may correlate with the likelihood and severity of allergic reactions, but even low-level sensitivities can potentially cause serious reactions in some individuals. Your healthcare provider will interpret results in conjunction with your clinical history and symptoms.
Important Considerations
The information here is for educational purposes only and is not a substitute for professional medical advice. Shellfish allergy can cause severe, life-threatening reactions. Always consult with a healthcare provider for proper diagnosis, treatment, and emergency action planning. If you suspect a shellfish allergy, avoid all shellfish until properly tested and evaluated by a medical professional.
