Allergy and intolerance
IgE voedingsallergenen
A panel of IgE tests against common foods; shows sensitization, not allergy.
Everything about this testWhat it measures
This test measures IgE antibodies against a range of common food allergens in one go, such as cow's milk, hen's egg, peanut, nuts, soy, wheat, fish and shellfish. IgE is the type of antibody that, in an allergic reaction, prompts mast cells to release histamine. The body only makes these antibodies after it has been in contact with the allergen before; this is called sensitization. Each allergen gives a value in kU/l; the laboratory indicates from which value a result counts as positive. Exactly which allergens are in the panel is stated on the result report.
- Sensitization to one or more foods from the panel
- Support in investigating a suspected food allergy, together with the story of the symptoms
- A starting point in assessing an earlier acute reaction shortly after eating
High
A value above the cutoff for one or more allergens means that you have IgE antibodies against them: sensitization. This is not the same as an allergy. With a panel, the chance is high that something comes out positive that has never given you symptoms. A positive result only counts if there has also been a clear reaction shortly after eating that food: itching in the mouth, hives, swelling, abdominal symptoms or shortness of breath within about two hours. Many positive results are due to cross-reaction: someone who is allergic to birch pollen can have antibodies against nuts, apple, soy or stone fruit and get at most itching in the mouth or throat.
Low
Values below the cutoff mean that no IgE antibodies against those foods have been found. An IgE-mediated food allergy is then a lot less likely for those allergens. Symptoms after eating can also have other causes, for example lactose intolerance, celiac disease, irritable bowel syndrome or a reaction to histamine in food; these are not found with this test. Also, not every food is in the panel.
If your result is abnormal
The GP mainly looks at the story: which food, 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.
Reliability
A positive IgE result shows sensitization, not allergy: it only says that there are antibodies, not that the food gives you symptoms. This applies even more strongly to a panel, because testing is done against many allergens at the same time, which considerably increases the chance of at least one positive result. The Dutch medical specialists' guideline (FMS) calls a supervised food challenge test the gold standard; a blood test cannot replace it. In people without clear symptoms after eating, the predictive value is low and a positive result is not treated.
Limitations
- A panel tests against many allergens at the same time; the chance that something comes out positive without giving you symptoms is therefore high.
- A pollen allergy, especially to birch pollen, often gives positive results for nuts, fruit and legumes without there being a true food allergy.
- According to the Dutch Society for Clinical Chemistry (NVKC), the level of the result says nothing about how severe a reaction would be.
- Symptoms that are not IgE-mediated, such as lactose intolerance, celiac disease or irritable bowel syndrome, are not found with this test.
How common is this
Many people think they cannot tolerate certain foods, but a true food allergy is much less common than that suspicion. In adults, it is estimated at a few percent; in young children it is somewhat higher, and some of the allergies disappear on their own. Sensitization without symptoms is much more common than the allergy itself.
Who is this useful for
The result says the most when there has been a clear reaction shortly after eating a particular food, as an addition to the conversation with the doctor. With vague symptoms such as tiredness, abdominal pain, headache or eczema without a clear link to a meal, a panel adds little. In people without symptoms, the chance of a positive result that means nothing is high, and according to the Dutch GP guideline (NHG), such a result is no reason to leave anything out of the diet.
Downsides and risks
- A panel often produces positive results for foods that you eat without problems. This can lead to unnecessarily cutting out foods, with a risk of a one-sided diet and, especially in children, of more rather than less allergy.
- Normal results do not rule out symptoms after eating: lactose intolerance, celiac disease and bowel complaints are not found with this test.
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