Tingling lips after crab claws, or hives after a seafood platter? Crab is a crustacean, like shrimp and lobster, and they share a main protein that survives cooking. Our test checks your blood for IgE to whole crab, as part of 300 allergens and allergen components, next to shrimp, lobster, house dust mite and cockroach.
The main crustacean allergen is tropomyosin, a muscle protein. Crab, shrimp, lobster and crayfish have tropomyosins that are almost identical. So people sensitised to crab are often sensitised to the other crustaceans too.
Tropomyosin survives boiling, so cooked crab still carries it. Some people react to the steam from boiling crab or to handling it raw.
House dust mites, cockroaches and edible insects also have a tropomyosin that resembles crab tropomyosin. Some people show crab IgE because of mite sensitisation, with or without symptoms from eating crab.
That is why it helps to see crab next to your dust mite and cockroach results. A doctor can tell a mite-driven pattern from a true shellfish pattern using your history and the full report.
Reactions people describe after shellfish include itching in the mouth, hives, swollen lips or face, vomiting, stomach cramps and wheezing. They usually start within minutes to two hours. Shellfish reactions often first appear in adults.
Swelling of the lips, tongue or throat, trouble breathing or feeling faint after eating is an emergency. Call 112 (EU) or your local emergency number. Do not wait for a test.
From a finger-prick sample, the lab measures IgE to a whole crab extract from snow crab. Shrimp (ten markers, including tropomyosin), lobster, squid and clam are on the same panel of 300 allergens and allergen components, together with house dust mite and cockroach tropomyosin.
Your lab report gives the value a class from Negative to Very high. That shows sensitisation, not a diagnosis. Discuss the result with a doctor before you change your diet.
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One finger-prick sample checks IgE to 300 allergens and allergen components, from birch and peanut to cat and house dust mite. Post it to the lab, and about 5 days after it arrives you get a value for every one. Our plain-English guide shows you how to read them. €399 in total, €1.33 per allergen.
Not necessarily. Crab sticks (surimi) are mostly fish, usually pollock, but many contain crab extract or flavouring. Check the label, and ask a doctor what fits your results.
Often, because crustaceans share nearly the same tropomyosin. Not everyone does. Your report shows crab, shrimp and lobster separately, so a doctor can see the full pattern.
In northern Germany, 'Krabben' often means small brown shrimp, as in Nordseekrabben, not crab. For IgE that matters less than you think: both are crustaceans with similar tropomyosin, and both are on the panel.
No. Shellfish reactions are to proteins such as tropomyosin, not iodine. If you are worried about contrast dye for a scan, tell the doctor doing it.
