Test Category · London
Shellfish & Fish Allergy Test London
Private IgE blood tests for crustacean, mollusc and finfish allergy at our nurse-led South Kensington clinic. Featuring Profile 11 (Combined Shellfish/Finfish — £239), Profile 6 (Shellfish — £298) and Profile 7 (Finfish — £298), plus single-allergen Tropomyosins and Parvalbumins component tests for cross-reactivity questions.
🚨 Shellfish & finfish are leading causes of adult anaphylaxis — call 999 for severe reactions
Shellfish allergy is one of the most common triggers of food-related anaphylaxis in UK adults. If you or someone you are with develops difficulty breathing, throat tightness, repeated vomiting, collapse, widespread hives or significant facial swelling after eating or being exposed to seafood, call 999, ask for an ambulance, and say "anaphylaxis". If a prescribed adrenaline auto-injector (such as EpiPen, Jext or Emerade) is available, use it without delay. See our anaphylaxis information page for more. Private blood testing is a diagnostic step — it does not replace emergency care, specialist review or carrying your adrenaline.
What Is a Shellfish or Fish Allergy Test?
A shellfish or fish allergy blood test measures specific IgE antibodies against the proteins in seafood. It is important to understand that shellfish and finfish are two completely different food groups with different allergenic proteins:
- • Shellfish includes crustaceans (shrimp, prawn, crab, lobster, crayfish) and molluscs (squid, octopus, scallop, mussels, oysters, clams). The main allergen is tropomyosin — a muscle protein shared across crustaceans.
- • Finfish (bony fish) includes cod, salmon, tuna, mackerel, sole, plaice and others. The main allergen is parvalbumin — a calcium-binding muscle protein shared across bony fish.
Being allergic to one does not mean you will be allergic to the other — they share no major cross-reactive proteins. That is why we offer separate Profile 6 (Shellfish) and Profile 7 (Finfish) panels, plus a combined Profile 11 if you want both investigated from a single sample.
As a CQC-registered, nurse-led diagnostic-only service, our role is to take a high-quality sample, generate a clearly formatted laboratory report, and release the results to you so you can share them with your GP or allergy specialist for clinical interpretation.
Allergy Profile 11 (Combined Shellfish/Finfish)
£239 · 2-day TAT · 6 allergens
The most cost-effective single-sample overview when you want both shellfish and finfish investigated together.
- · Cod
- · Prawn / Shrimp
- · Salmon
- · Scallop
- · Squid
- · Tuna
Allergy Profile 6 (Shellfish)
£298 · 2-day TAT · 8 allergens
The deepest shellfish panel — covers both crustaceans and molluscs in one sample for a more complete cross-reactivity picture.
- · Clam
- · Crab
- · Crawfish / Crayfish
- · Lobster
- · Octopus
- · Prawns / Shrimp
- · Scallop
- · Squid
Allergy Profile 7 (Finfish)
£298 · 2-day TAT · 8 allergens
The deepest bony-fish panel — useful when reactions have occurred to one fish and you want to understand the risk across different species.
- · Codfish
- · Mackerel
- · Plaice
- · Sardine / Pilchard
- · Salmon
- · Sole
- · Swordfish
- · Tuna
Seafood Cross-Reactivity Explained
One of the most useful things a structured blood test can do is help map out which seafood groups are likely to cross-react and which probably will not. The picture depends on which protein your IgE is targeting — primarily tropomyosin (for shellfish) and parvalbumin (for finfish).
| If you react to... | Likely cross-reactivity | Why (protein) | Suggested test |
|---|---|---|---|
| Shrimp | High (~75%) with other crustaceans: crab, lobster, crayfish | Tropomyosin — highly conserved across crustaceans | Profile 6 + Tropomyosins component |
| Shrimp | Variable / less predictable with molluscs (squid, scallop, oyster) | Mollusc tropomyosin is less similar to crustacean tropomyosin | Profile 6 (includes molluscs) |
| Cod | High (~50%) with other bony fish: salmon, tuna, mackerel, plaice | Parvalbumin — highly conserved across bony fish | Profile 7 + Parvalbumins component |
| Shellfish | Low with finfish — different food group, different proteins | No major shared allergens | Profile 11 if both need clarifying |
| Crustaceans | Possible link with house dust mite allergy | Both contain tropomyosin (mite tropomyosin = Der p 10) | Tropomyosins component test |
| Raw fish only (sushi) | Consider Anisakis (a fish parasite) rather than fish itself | A parasitic, not fish-protein, allergic reaction | Discuss with GP / specialist — we do not currently offer Anisakis testing |
Cross-reactivity percentages are rough population-level estimates from peer-reviewed allergy literature; your individual pattern may differ. Your GP or allergy specialist interprets your IgE results in context — please do not add foods back into your diet on the basis of a blood-test result alone.
Shellfish & Fish Allergy Tests We Offer
Profiles 11, 6 and 7 appear first as our headline panels, followed by single-allergen component tests (cheapest first) and broader multiplex options. Click any test for the full description, sample type and turnaround time.
Allergy Profile 11 (Combined Shellfish/Finfish)
Allergy Profile 6 (Shellfish)
Allergy Profile 7 (Finfish)
Total IgE
Shrimp Components
Fish Components
Parvalbumins
Tropomyosins
ALEX³ Allergy Test (Venous)
Which Test Is Right for You?
The summary below is for general orientation only. Your GP or allergy specialist can advise on the most appropriate panel for your symptom pattern.
| If you... | A common starting point |
|---|---|
| Are unsure whether you reacted to shellfish or fish and want one cost-effective overview | Profile 11 (Combined Shellfish/Finfish) — £239 |
| Have reacted to shrimp / prawn and want to know about other shellfish (crustaceans + molluscs) | Profile 6 (Shellfish) + Tropomyosins component |
| Have reacted to cod and want to know about other bony fish | Profile 7 (Finfish) + Parvalbumins component |
| Already know you have a strong dust mite allergy and react to shellfish | Tropomyosins component — explores the shared protein |
| Want the broadest single-sample picture across all seafood + other food groups | ALEX² multi-allergen test (~300 allergens) |
| Have reacted only to raw or undercooked fish (sushi, sashimi) | Discuss Anisakis (fish parasite) testing with your specialist — we do not offer this test |
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.
Transparent Pricing
- → Profile 11 (Combined Shellfish/Finfish) £239 — 6-allergen overview panel, 2-day turnaround.
- → Profile 6 (Shellfish) £298 — 8-allergen crustacean + mollusc panel, 2-day turnaround.
- → Profile 7 (Finfish) £298 — 8-allergen bony-fish panel, 2-day turnaround.
- → Tropomyosins £119 and Parvalbumins £119 — single-allergen cross-reactivity components, 2-day turnaround. Useful add-ons when the main panel raises a specific question.
- → Each price is the all-inclusive fee for the laboratory test, sample collection by a registered nurse at our South Kensington clinic and a written laboratory report.
- → No GP referral is required. You can book directly online.
- → We do not charge for the appointment itself — only for the test you choose.
- → All prices are inclusive of VAT where applicable.
We cannot guarantee that private testing will be reimbursed by insurance providers — please check with your insurer before booking.
Our Role in the Diagnostic Pathway
AllergyClinic.co.uk is a CQC-registered, nurse-led diagnostic service. All blood samples are taken by registered nurses experienced in allergy and component-resolved testing pathways, processed by an accredited laboratory, and returned to you as a clearly formatted report. We do not diagnose shellfish or fish allergy, prescribe adrenaline auto-injectors, issue or alter emergency action plans, or recommend dietary restriction — those steps sit with your GP and, where indicated, an allergy specialist or registered dietitian.
A typical UK pathway for suspected seafood allergy is: GP review → IgE blood testing (component-resolved where useful) → allergy specialist referral if reactions have been systemic, severe or unclear → individualised dietary and emergency-management advice from a specialist and/or registered dietitian. Private blood testing through our clinic can be a useful intermediate step to bring well-organised results to your GP appointment.
Cross-reactivity figures and population-level statistics in this guide are taken from peer-reviewed allergy literature and are for general orientation only. Individual results vary, and the same laboratory result may have different clinical meaning depending on the person and their reaction history — please do not reintroduce foods after a previous reaction, or relax existing avoidance, on the basis of a blood-test result alone.
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 Conditions
Related Reading
Frequently Asked Questions
What is the difference between shellfish and finfish allergy?
Shellfish (crustaceans like shrimp, prawn, crab, lobster and molluscs like squid, scallop, oyster) and finfish (cod, salmon, tuna, mackerel) are completely different food groups containing different allergenic proteins. The main shellfish allergen is tropomyosin; the main finfish allergen is parvalbumin. Being allergic to one does NOT mean you will be allergic to the other — which is why we offer separate panels for each, plus a combined Profile 11 if you are investigating both.
If I am allergic to shrimp, am I allergic to all shellfish?
Cross-reactivity between crustaceans (shrimp, crab, lobster, crayfish) is very common because they all share the same tropomyosin protein — studies suggest around 75% of people with one crustacean allergy will react to others. Cross-reactivity with molluscs (squid, octopus, scallop, mussels, oysters) is much less predictable. A blood test panel that covers both crustaceans and molluscs (like our Profile 6) can help your specialist build a clearer picture.
What do the Tropomyosins and Parvalbumins component tests show?
Tropomyosins (£119) measure IgE to the muscle protein shared by all crustaceans, dust mite and cockroach — useful when a clinician wants to understand whether crustacean reactions are likely to cross over to other crustaceans, and whether dust mite sensitisation might be relevant. Parvalbumins (£119) measure IgE to the calcium-binding muscle protein shared by all bony fish — useful for understanding whether someone reacting to one fish (e.g. cod) is likely to react to others (e.g. salmon, tuna).
Do I need to stop eating seafood before the blood test?
No. IgE blood tests measure circulating antibodies and are not affected by recent meals, antihistamines or other allergy medications. You can eat normally before the appointment and continue any prescribed medication. There is no need to fast.
Can a blood test alone confirm a seafood allergy?
No. A positive IgE result shows sensitisation — that your immune system has produced antibodies against that allergen — but a clinical diagnosis of food allergy is made by a GP or allergy specialist who weighs the test result against your symptom history. Some people are sensitised without ever reacting clinically; some people with very low IgE levels still react. In ambiguous cases your specialist may consider a supervised food challenge.
My reaction happened after sushi or raw fish — could it be something other than fish allergy?
Possibly. Reactions to raw or undercooked fish can occasionally be caused by Anisakis (a fish parasite), not by the fish itself. Anisakis allergy is sometimes misdiagnosed as fish allergy in regular sushi eaters. We do not offer an Anisakis-specific blood test; if your reactions are exclusively to raw or lightly cooked fish but you tolerate well-cooked fish, please mention this to your GP or specialist so the right investigations can be arranged.
What about histamine fish poisoning — is that an allergy?
No. Scombroid (histamine) fish poisoning is caused by eating spoiled fish (typically tuna, mackerel or mahi-mahi) in which bacterial action has converted histidine into histamine. The symptoms (flushing, headache, rash, palpitations) look very like an allergic reaction but are toxic rather than allergic. An IgE blood test will be negative — diagnosis is clinical, based on the link to a suspect meal and other diners affected.
Do I need a GP referral, and will my insurance cover this?
No GP referral is required — you can book directly online. We cannot guarantee that private blood testing will be reimbursed by your insurance provider; please check with your insurer before booking. The price shown is the all-inclusive cost of the laboratory test, sample collection by a registered nurse, and a written laboratory report.
Related reading
Shellfish Allergy Symptoms: Crustaceans vs Molluscs
Shellfish allergy symptoms: how crustacean and mollusc reactions differ, why tropomyosin matters, and which IgE component tests pinpoint your specific triggers.
Read article →
Shellfish vs. Mollusc: Understanding Your Seafood Diagnostic Profile
Shellfish allergy symptoms explained. Learn why prawn allergy differs from squid allergy, tropomyosin cross-reactivity, crustacean vs mollusc IgE testing, and UK seafood labelling rules.
Read article →Clarify Your Seafood Allergy Picture
Three structured panels covering crustaceans, molluscs and bony fish, plus single-allergen tropomyosin and parvalbumin components for cross-reactivity questions. Sample collected by a nurse at our South Kensington clinic — results released to you to share with your GP or allergy specialist.
See the tests & pricing →