Itchy and blotchy after a grilled swordfish steak in Sicily or the Algarve? In northern Europe swordfish is mostly a holiday or restaurant fish, so a reaction often comes as a surprise. Our test checks your blood for IgE to swordfish parvalbumin, as part of 300 allergens and allergen components, next to seven other fish.
Swordfish is a large ocean bony fish. Its main allergen is parvalbumin, a small muscle protein called Xip g 1. Parvalbumins from different bony fish look alike, so IgE to swordfish often comes with IgE to tuna, cod or other fish.
Parvalbumin survives grilling and frying well. So a well-cooked swordfish steak still carries it.
Reactions people describe after eating fish include itching in the mouth, hives, swollen lips, stomach cramps, vomiting and wheezing. They usually start within minutes to two hours.
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.
A reaction after a restaurant meal abroad has many possible causes. Large fish such as swordfish and tuna can build up histamine if they warm up after the catch. That causes flushing, headache and a rash in anyone, and it is food poisoning, not an allergy.
Sauces and sides can hide other allergens too, such as shellfish, nuts or mustard. Testing swordfish next to the rest of the panel helps narrow it down before your next trip.
From a finger-prick sample, the lab measures IgE to swordfish parvalbumin, a single protein (molecular component). There is no whole swordfish extract on the panel. Cod, salmon, herring, mackerel, tuna, carp and thornback ray are on the same panel of 300 allergens and allergen components.
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.
Ask a doctor first. Swordfish parvalbumin resembles that of cod, tuna and salmon, so sensitisation to several fish is common. Testing eight fish side by side shows your pattern for a doctor to read.
No. Mercury advice for swordfish is about toxicity, mainly for pregnant women and young children. It has nothing to do with IgE allergy, and it does not show on this test.
It could. Swordfish and tuna that warm up after the catch can build up histamine, which causes flushing and a rash in anyone. An IgE allergy usually repeats each time you eat the fish. A test shows whether your blood has IgE to swordfish.
