Allergy and intolerance
IgE antilichamen kippenei
Antibodies against egg protein; shows whether the immune system is sensitive to hen's egg, not whether it gives you symptoms.
Everything about this testWhat it measures
This test measures the amount of IgE antibodies against the proteins in hen's egg in the blood. IgE is the type of antibody that, in an allergic reaction, prompts mast cells to release histamine. The body only makes such antibodies after it has been in contact with the allergen before; this is called sensitization. The result is a number in kU/l; the laboratory indicates from which value the result counts as positive.
- Sensitization to hen's egg: the body has made IgE antibodies against hen's egg
- Support in investigating a suspected allergy to hen's egg, together with the story of the symptoms
- Support with the question of whether an earlier reaction to eating egg fits an allergy
High
A value above the cutoff means that you have IgE antibodies against hen's egg: sensitization. This is not the same as an allergy. Egg allergy mainly occurs in young children and usually goes away again: by the age of four, most children have outgrown it. The IgE result often stays positive for a long time while the child already tolerates egg again; that is why the result can only be assessed properly together with the symptoms or a food challenge test. It also makes a difference whether egg is eaten raw or well heated: someone who tolerates cooked egg can still react to raw egg. According to the Dutch Society for Clinical Chemistry (NVKC), the level of the result says nothing about how severe a reaction would be, although a clearly higher value does go with a greater chance that there really is an allergy.
Low
A value below the cutoff means that no IgE antibodies against hen's egg have been found. An IgE-mediated allergy to hen's egg is then a lot less likely. According to the Dutch medical specialists' guideline (FMS), with a negative result the chance of an IgE-mediated egg allergy is negligibly small in groups that have been studied for it. Symptoms after eating can also have another cause, for example an intolerance or a bowel condition.
If your result is abnormal
The GP mainly looks at the story: which symptoms, how soon after eating and how often. Often a food diary follows, along with temporarily leaving out the suspected food and then reintroducing it. If a true allergy is suspected or after a severe reaction, a referral follows to an allergist or pediatrician, where a food challenge test is done if needed; according to the Dutch medical specialists' guideline (FMS), this test is the gold standard.
Reliability
A positive IgE result shows sensitization, not allergy: it only means that there are antibodies, not that hen's egg gives you symptoms. The pooled specificity of the IgE test for hen's egg in the Dutch medical specialists' guideline (FMS) is 49 percent: about half of the people studied without an egg allergy still have a positive result. Because a positive result also occurs in people without an allergy, the result can cause confusion when viewed separately from the symptoms. The result can only be interpreted together with the story of the symptoms and, if in doubt, with a food challenge test in the hospital.
Limitations
- In children, the result often stays positive after the allergy has already gone away.
- The test does not distinguish between reacting to raw egg and to well-heated egg.
- Eggs of other birds contain similar proteins; eating chicken or other poultry, on the other hand, rarely causes symptoms.
- Laboratories use different measuring methods; results from different labs cannot always be compared one to one.
How common is this
Allergy to hen's egg occurs in about 2 in 100 young children. By the age of four, it has disappeared in most of them; fewer than 1 in 100 adults remain allergic to egg. According to the Dutch medical specialists' guideline (FMS), food allergy in general occurs in 2 to 3 in 100 children aged 0 up to and including 4.
Who is this useful for
The result says the most when there has been a clear reaction shortly after eating hen's egg, as an addition to the conversation with the doctor. In people who eat hen's egg normally and have never had an acute reaction to it, a positive result does not mean that you are allergic and can lead to unnecessarily avoiding egg. With vague symptoms such as abdominal pain, tiredness or eczema without a clear link to a meal, the test adds little. For babies and young children, testing preferably goes through the GP, the child health clinic or the pediatrician.
Downsides and risks
- A positive result without symptoms easily leads to hen's egg being unnecessarily left out of the diet. This can lead to a shortage of nutrients and, according to Thuisarts.nl, can actually increase the chance of an allergy, especially in children.
- A normal result does not rule out symptoms caused by hen's egg: there are people with symptoms in whom no IgE antibodies can be found in the blood.
Sources
Always discuss an abnormal result with your GP. If a result is strongly abnormal, we try to reach you as soon as possible. Read your result yourself as well and contact your GP if in doubt. A test does not make a diagnosis. Read more about risks and results