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Blood Test Tracker

Egg White IgE

Measures IgE antibodies to egg white in your blood. A detectable result means your immune system is sensitized to egg, which is not the same as an allergy.

AI-verified against cited sources. Awaiting expert reviewAlso called f1, f001LOINC 6106-9

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What it is

IgE is a type of antibody your immune system can make against a food protein. This test measures IgE to egg white (also written f1) using a method called ImmunoCAP. Egg white holds several proteins, including ovomucoid (Gal d 1), ovalbumin (Gal d 2), ovotransferrin (Gal d 3) and lysozyme (Gal d 4), and this test looks at egg white as a whole. Results come in kilounits per liter (kU/L), and many labs also print a class from 0 to 6. Egg allergy is mostly a childhood condition, and many children outgrow it.

Why it matters

Egg is one of the most common food allergies in young children. This test can help you and your clinician look at whether egg might be behind symptoms such as hives, vomiting or eczema flares after eating it. On its own it cannot confirm an allergy, because many people with IgE to egg eat it without trouble. Your history of symptoms matters most, and sometimes a supervised food challenge is the way to find out. For children, doctors may also follow the level over time.

If it’s high

A level above your lab's range means your body has made more IgE to egg white. In general, higher levels make a reaction to egg more likely, but the link is not exact, and the number does not predict how strong a reaction would be. Some people with high levels eat egg with no problem. Your clinician reads the number together with your symptoms.

Common causes

  • Sensitization without symptoms, where you make the antibody but eat egg with no problem
  • A true egg allergy, which is most common in young children
  • Eczema (atopic dermatitis) and other allergic conditions, which often go along with IgE to foods
  • A very high total IgE (above about 2,500 kU/L), which can cause a false-positive reading

What can help

  • Talk with an allergist about how this result fits your or your child's history with egg
  • Ask whether a component test such as Gal d 1 (ovomucoid) would help, especially if baked egg is the question
  • Ask whether a skin test or a supervised food challenge would help clarify the result
  • Check with your clinician before adding egg back to the diet or cutting it out

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: Mayo Clinic Laboratories, ARUP Laboratories, U.S. Food and Drug Administration, Journal of Allergy and Clinical Immunology.

ImmunoCAP IgE classes (Mayo Clinic Laboratories wording)

  • Class 0: negativebelow 0.1 kU/L
  • Class 0/1: borderline or equivocal0.1 to under 0.35 kU/L
  • Class 1: equivocal0.35 to under 0.7 kU/L
  • Class 2: positive0.7 to under 3.5 kU/L
  • Class 3: positive3.5 to under 17.5 kU/L
  • Class 4: strongly positive17.5 to under 50 kU/L
  • Class 5: strongly positive50 to under 100 kU/L
  • Class 6: strongly positive100 and above kU/L

What can affect your result

  • Age: egg allergy is most common in young children, and most egg-allergic children develop tolerance over time
  • How egg is prepared: some children who react to lightly cooked egg tolerate extensively baked egg, so cooking matters to the clinical picture
  • Other allergies and eczema, which are linked to food sensitization
  • A very high total IgE (above about 2,500 kU/L) can cause false-positive results
  • The lab and test brand, because results from different systems are not directly comparable
  • A very high total IgE (above about 2,500 kU/L) can cause false-positive results through nonspecific binding (Mayo Clinic Laboratories).
  • Different labs and test brands give different numbers for the same blood sample, so compare results from the same lab and system.
  • Some labs reject hemolyzed, icteric or lipemic samples (ARUP).

Slow. It usually shifts over months to years, not weeks.

When to talk to a clinician

Call 911 or your local emergency number right away if any of these happen after eating egg or a food that may contain it: trouble breathing, swelling of the lips, tongue or throat, dizziness or fainting, repeated vomiting, or widespread hives. Do not wait for a lab result. For milder or past symptoms, talk with a clinician or allergist even if this result is in the usual range.

Questions you could ask

  • How often, if at all, should we recheck this?
  • What does this result mean given my or my child's history with egg?
  • Would a Gal d 1 (ovomucoid) test help, especially for baked egg?
  • Would a skin test or a supervised food challenge help clarify the result?
  • My result is in the usual range but I have had symptoms after egg. What should we do next?

Questions people ask

My child's egg white IgE is positive. Does that mean an egg allergy?

Not by itself. A positive result means your child's immune system has made IgE to egg, which is called sensitization. Many sensitized children eat egg without problems. An allergy is diagnosed when egg causes symptoms, so your clinician looks at the result with your child's history and sometimes a supervised food challenge.

Can children outgrow egg allergy, and what about baked egg?

Many do. Most egg-allergic children develop tolerance over time, and some who react to lightly cooked egg can eat extensively baked egg, such as in muffins. Only an allergist can decide whether and how to test that safely, so do not try it at home without their guidance.

What do the classes 0 to 6 on my report mean?

Labs sort the number into classes. Class 0 is below about 0.10 kU/L, and each higher class covers a higher level of IgE, up to class 6 at 100 kU/L or more. The class describes how much IgE was found, not how serious a reaction would be. Labs flag results at different points, so use the range printed on your own report.

Show the science and sources

For clinicians and researchers

Quantitative IgE to a whole egg white extract (ImmunoCAP f1). Reported as allergen-specific IgE by ImmunoCAP fluoroenzyme immunoassay in kUA/L, with calibrators traceable to the WHO IgE reference (IRP 75/502). The FDA-reviewed system has a limit of quantitation of 0.1 kUA/L and reports up to 100 kUA/L; its maker recommends a 0.35 kUA/L cutoff and tells each lab to set its own range (FDA review K173726). The major egg white allergens are ovomucoid (Gal d 1, heat- and digestion-stable, about 11% of egg white protein), ovalbumin (Gal d 2, heat-labile, about 54%), ovotransferrin (Gal d 3) and lysozyme (Gal d 4); component IgE to Gal d 1 (f233) is used to help judge reactivity to heated egg and persistence (Mayo Clinic Laboratories, Thermo Fisher). Most hen's egg white allergens cross-react with egg white proteins from turkey, duck, goose and gull (Thermo Fisher). Allergen-specific IgE shows sensitization, not clinical allergy: the NIAID-sponsored guidelines state that sensitization alone is not sufficient to define food allergy, and that further evaluation such as an oral food challenge is needed to confirm a diagnosis. Published decision points and natural-history data differ by age, population and assay, and should not be applied outside the setting they came from. Nonspecific binding can cause false positives when total IgE exceeds about 2,500 kU/L (Mayo). Immulite 2000 and ImmunoCAP agree well for common allergens, but the authors of a head-to-head comparison still call for better harmonization of sIgE tests (Scand J Clin Lab Invest 2018).

LOINC 6106-9 (primary), 112162-3. Specimen: serum.

Sources

  1. Egg White, IgE, Serum (test ID EGG), Mayo Clinic Laboratories
  2. Egg White Component Profile, Serum (test ID EGWTP), Mayo Clinic Laboratories
  3. Allergen, Food, Egg White (ARUP test 0055013), ARUP Laboratories
  4. Egg White (F001-IgE Egg White) (Labcorp test 602452), Labcorp
  5. ImmunoCAP Specific IgE (allergen component f447) 510(k) decision memorandum K173726, U.S. Food and Drug Administration
  6. Guidelines for the Diagnosis and Management of Food Allergy in the United States: Report of the NIAID-Sponsored Expert Panel, Journal of Allergy and Clinical Immunology (2010)
  7. f1 Egg white (Allergen Encyclopedia), Thermo Fisher Scientific (Phadia)
  8. Specific IgE antibody criteria for Japanese cedar, Uni-CAP method (Appendix 3, in Japanese), Ministry of the Environment, Japan
  9. Allergy Testing units (LOINC Community Forum thread), Regenstrief Institute, LOINC Community Forum
  10. Comparison of allergen-specific IgE levels between Immulite 2000 and ImmunoCAP systems against six inhalant allergens and ten food allergens, Scandinavian Journal of Clinical and Laboratory Investigation (2018)

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

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