Shellfish Allergy Testing
View All TestsWhat Is Shellfish Allergy?
Shellfish allergy is an IgE-mediated food allergy to crustaceans (shrimp, crab, lobster, crayfish) and/or molluscs (mussels, oysters, squid, scallops). It is the most common food allergy in adults in the UK and tends to persist lifelong.
The major allergen in crustaceans is tropomyosin, a muscle protein found across many invertebrate species. This means shellfish-allergic individuals may also experience cross-reactivity with house dust mites, cockroaches, and other crustacean species — all of which contain structurally similar tropomyosins.
If you have a known shellfish allergy with a history of severe reactions, always follow your existing emergency action plan.
How Testing Works
Choose Your Test
Select from our range of allergy blood tests and book a convenient time at our South Kensington clinic. No GP referral needed.
Nurse Blood Draw
A qualified nurse takes a small blood sample at our clinic. The appointment is quick and straightforward.
Get Your Results
Results are sent directly to you, typically within a few working days. Share them with your GP or specialist to guide your next steps.
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Why Choose a Diagnostic-Only Clinic?
Unlike clinics that provide both testing and treatment, our nurse-led service focuses solely on accurate diagnostic testing. Because we don't offer treatments or prescriptions, there is no commercial incentive to recommend unnecessary tests — just honest, impartial results you can trust.
Nurse-Led & Impartial
Our qualified nurses collect your sample — we don't prescribe, treat, or have any reason to upsell.
Results You Own
Your results are sent directly to you. Take them to your GP or a specialist to discuss what's best for your situation.
You Stay in Control
Understand your allergy profile, then decide with your healthcare professional what steps to take next.
Related Reading
Frequently Asked Questions
If I am allergic to shrimp, am I allergic to all shellfish?
Cross-reactivity between crustaceans (shrimp, crab, lobster) is common due to shared tropomyosin proteins. Cross-reactivity with molluscs (mussels, squid) is less predictable. Comprehensive testing can help your specialist clarify your individual risk profile.
Can shellfish allergy cross-react with dust mite allergy?
Yes. Tropomyosin is found in both shellfish and dust mites. Some individuals sensitised to dust mite tropomyosin may test positive to shellfish even without clinical symptoms. Component testing helps distinguish true allergy from cross-sensitisation.
Do I need a GP referral for allergy testing?
No. You can book directly with our clinic without a GP referral. Simply choose your test and select a convenient appointment time. If you're unsure which test is right for your symptoms, our team can help guide your selection.
Do I need to stop taking antihistamines before a blood test?
No. Unlike skin prick testing, IgE blood tests are not affected by antihistamines or other allergy medications. You can continue taking your regular medications before your appointment.
What should I do with my results?
As a diagnostic-only clinic, we provide results directly to you. We recommend sharing them with your GP or allergist for clinical interpretation and dietary guidance.
Get Detailed Shellfish Allergy Testing
Book a blood test at our South Kensington clinic
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