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Blood Test Tracker

Salmon IgE

Shows whether your immune system has made IgE antibodies to salmon. This is called sensitization and doesn't always mean a fish allergy.

AI-verified against cited sources. Awaiting expert reviewAlso called f41, F041LOINC 6237-2

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What it is

Salmon is a popular fish, and this test uses Atlantic salmon (Salmo salar). It measures IgE, the antibody type linked to allergic reactions, that your body has made against salmon. The main salmon allergen is a small muscle protein called parvalbumin (Sal s 1). It survives cooking and is similar in many kinds of fish, so IgE to salmon often shows up for other fish too. Sensitization means your body has made IgE antibodies to a substance. It does not always mean you are allergic.

Why it matters

Fish allergy can cause reactions that range from hives and stomach upset to a serious reaction called anaphylaxis. A positive salmon result shows that IgE is present. It does not prove you are allergic, and many sensitized people eat fish without trouble. A negative result also doesn't fully rule out an allergy. Your history of reactions matters most, and an allergy specialist may use a supervised food challenge to settle the question.

If it’s high

A result above your lab's usual range means your body has made IgE antibodies to salmon. It is more likely to match a true fish allergy if you have had symptoms soon after eating salmon. The number alone can't tell how strong a reaction would be, and no blood test can predict how severe a future reaction will be.

Common causes

  • A true fish allergy, with symptoms soon after eating salmon
  • Sensitization without symptoms, which is common with food IgE tests
  • Cross-reaction with parvalbumin, the shared protein in many fish, so salmon IgE can be positive in people who react to cod or other fish
  • A weak result of 0.10 to 0.34 kU/L, which labs treat as uncertain

What can help

  • If you have had symptoms after eating salmon, talk with your clinician before eating it again
  • Ask whether an allergy specialist could test other kinds of fish and decide if a supervised food challenge makes sense
  • Ask for a written plan for what to do if you have a reaction

Usual ranges

What labs print as the reference range, by who was tested. Ranges differ a little between labs, so the range on your own report is the one your result is judged against.

For adults: 0–0.09 kU/L. Source: Labcorp, ARUP Laboratories, Quest Diagnostics, Thermo Fisher Scientific (Phadia), NIAID / Journal of Allergy and Clinical Immunology, Clinical Reviews in Allergy & Immunology, Journal of Allergy and Clinical Immunology, MedlinePlus (National Library of Medicine).

ImmunoCAP class scale as printed by Quest and ARUP (labs differ on which class an exact edge value falls in)

  • Class 0: absent or undetectablebelow 0.1 kU/L
  • Class 0/1: very low level, relevance uncertain0.1 to under 0.35 kU/L
  • Class 1: low level0.35 to under 0.7 kU/L
  • Class 2: moderate level0.7 to under 3.5 kU/L
  • Class 3: high level3.5 to under 17.5 kU/L
  • Class 4: very high level17.5 to under 50 kU/L
  • Class 5: very high level50 to under 100.01 kU/L
  • Class 6: very high level100.01 and above kU/L

Labcorp class scale (ImmunoCAP, as printed on Labcorp reports)

  • Class 0: negativebelow 0.1 kU/L
  • Class 0/I: equivocal or low0.1 to under 0.32 kU/L
  • Class I: low0.32 to under 0.56 kU/L
  • Class II: moderate0.56 to under 1.41 kU/L
  • Class III: high1.41 to under 3.91 kU/L
  • Class IV: very high3.91 to under 19.01 kU/L
  • Class V: very high19.01 to under 100.01 kU/L
  • Class VI: very high100.01 and above kU/L

What can affect your result

  • Species: salmon IgE often cross-reacts with other fish, but IgE to another fish doesn't always mean you react to it when you eat it
  • Cooking: parvalbumin is very heat-stable, so cooking does not remove it. Some fish, such as tuna, contain much less of it than salmon, trout or cod.
  • Fish meat versus fish eggs (roe): they have different main allergens, so a salmon result may not reflect a reaction to roe
  • Breathing in steam from cooking or processing fish can also cause symptoms in sensitized people
  • Lab method: results from different labs or assay systems may not be comparable
  • Results from different labs and test brands are not directly comparable, so compare results from the same lab and method (NIAID 2010).
  • Labs may reject samples that are hemolyzed (red cells broken), jaundiced (icteric) or lipemic (very fatty). ARUP lists all three as unacceptable.
  • MedlinePlus notes that some medicines, such as antihistamines, may matter before an allergy blood test. Tell your clinician about everything you take and ask them what applies to you.

Antibody levels usually change slowly, over months to years.

When to talk to a clinician

Call your local emergency number if, soon after eating salmon or other fish, you have trouble breathing, throat tightness, swelling of the lips or tongue, repeated vomiting, dizziness or fainting. See a clinician soon if you get hives, itching or stomach upset after eating salmon or other fish.

Questions you could ask

  • How should I read this result if I've never had a reaction to salmon?
  • Does this result fit the symptoms I've had after eating salmon?
  • Should I see an allergy specialist, and would testing for other kinds of fish help?
  • Is a supervised food challenge appropriate for me?
  • What should my plan be if I have a reaction?

Questions people ask

If my salmon result is positive, do I have to avoid all fish?

Not necessarily. Many fish share the same protein, so IgE to salmon often shows up for other fish, but reports vary widely on how often people also react when they eat other fish. Some fish, such as tuna, have much less of the protein and are often tolerated. An allergy specialist can test and, if it makes sense, supervise safe trials. If you have had a reaction, talk with your clinician before trying other fish.

Can I have a negative result and still be allergic?

It's uncommon, but yes. Undetectable IgE can happen in people with an IgE-mediated food allergy. If your history strongly suggests a reaction, your clinician may suggest a supervised food challenge before you eat the food again.

Does a salmon result tell me about salmon roe (eggs)?

Not reliably. Fish meat and fish eggs have different main allergens, so people who react to one can often eat the other. Ask your clinician whether roe needs separate attention for you.

Show the science and sources

Units

  • 1 kU/L = 1 kU/L
  • 1 kU/L = 1 UA/mL

For clinicians and researchers

ImmunoCAP f41 is a fluorescent enzyme immunoassay for IgE to an Atlantic salmon (Salmo salar) extract. The major allergen, Sal s 1, is a beta-parvalbumin, a heat-stable panallergen across fish species. Enolase (Sal s 2) and aldolase (Sal s 3) are less stable minor allergens, and vitellogenin in fish roe is a separate allergen, so people who react to roe can often eat fillet and the reverse (Dijkema 2022). About half of cod-allergic patients are reported to cross-react to salmon, with 58% amino acid homology between cod Gad c 1 and salmon Sal s 1 (Thermo Fisher). In the NIAID 2010 summary table, codfish versus other fish showed IgE cross-reactivity in 5% to 100% and clinical reactivity in 30% to 75% of studied patients, so serologic cross-reactivity does not equal clinical cross-reactivity. Some patients have clinically relevant mono-sensitization to salmonid fish through a species-specific parvalbumin epitope, and tolerance of a fish relates to its parvalbumin content (about 1 to 2.5 mg/g in salmon, trout and cod, 0.3 to 0.7 in mackerel and under 0.05 in tuna, per the review). Undetectable IgE occasionally occurs in IgE-mediated food allergy, which is why a supervised oral food challenge remains the reference standard. ARUP also offers salmon as part of a six-fish profile (codfish, tuna, mackerel, halibut, salmon, trout).

LOINC 6237-2 (primary), 112095-5. Specimen: serum.

Sources

  1. F041-IgE Salmon (test 602507), Labcorp
  2. Sample patient report: F041-IgE Salmon (test 602507), Labcorp
  3. Allergen, Food, Salmon (test 0099680), ARUP Laboratories
  4. Allergens, Food, Fish Profile IgE (test 2007036), ARUP Laboratories
  5. ImmunoCAP Specific IgE Blood Test: Allergy Test List (interpretation table and test codes), Quest Diagnostics (2017)
  6. Your quick guide to using ImmunoCAP Specific IgE testing, Thermo Fisher Scientific (Phadia)
  7. Allergen Encyclopedia: f41 Salmon (Atlantic), Thermo Fisher Scientific (Phadia)
  8. Guidelines for the Diagnosis and Management of Food Allergy in the United States: Report of the NIAID-Sponsored Expert Panel, NIAID / Journal of Allergy and Clinical Immunology (2010)
  9. Fish Allergy: Fishing for Novel Diagnostic and Therapeutic Options, Clinical Reviews in Allergy & Immunology (2022)
  10. Prevalence of allergic sensitization in the United States: results from the National Health and Nutrition Examination Survey (NHANES) 2005-2006, Journal of Allergy and Clinical Immunology (2014)
  11. Allergy Blood Test, MedlinePlus (National Library of Medicine)

AI-verified against cited sources. Awaiting expert review. Last reviewed 2026-10-03. How we build and check these pages.

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