Allergy and intolerance
IgE antilichamen tarwe
Antibodies against wheat protein; shows whether the immune system is sensitive to wheat. It is not a test for celiac disease.
Everything about this testWhat it measures
This test measures the amount of IgE antibodies against the proteins in wheat 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 states from which value the result counts as positive.
- Sensitization to wheat: the body has made IgE antibodies against wheat
- Support in looking into a suspected wheat allergy, together with the story of the symptoms
- Support in answering whether symptoms after bread or pasta fit a wheat allergy
High
A value above the cut-off means you have IgE antibodies against wheat: sensitization. That is not the same as an allergy. A wheat allergy is something different from celiac disease: in celiac disease the immune system reacts to gluten and damages the bowel, and this test cannot show that. Positive results without symptoms are common, partly due to cross-reaction with grass pollen. In some people with a wheat allergy, symptoms only occur if they exercise within an hour after eating; this form is called WDEIA. According to the Dutch Society for Clinical Chemistry (NVKC), the height of the result says nothing about how severe a reaction would be, although a clearly higher value does go with a higher chance that there really is an allergy.
Low
A value below the cut-off means that no IgE antibodies against wheat were found. A wheat allergy that works through IgE is then a lot less likely. A normal result rules out wheat allergy less well than for peanut or egg. According to the Dutch medical specialists' guideline (FMS), the protein omega-5 gliadin, which belongs to the exercise-related form, is barely present in the test fluid used. 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 and then reintroducing the suspected food. If a real allergy is suspected or after a severe reaction, you are referred to an allergist or pediatrician, where a food challenge is done if needed; according to the Dutch medical specialists' guideline (FMS), that test is the gold standard.
Reliability
A positive IgE result shows sensitization, not allergy: it only means there are antibodies, not that you get symptoms from wheat. The pooled specificity of the IgE test for wheat in the Dutch medical specialists' guideline (FMS) is 43 percent: more than half of the people studied without a wheat allergy still test positive. Because a positive result also occurs in people without an allergy, the result can cause confusion when looked at apart from the symptoms. The result can only be interpreted together with the story of the symptoms and, in case of doubt, with a food challenge in hospital.
Limitations
- This test can neither show nor rule out celiac disease or gluten sensitivity without allergy.
- A grass pollen allergy often gives a positive result without any symptoms from wheat.
- The form of wheat allergy in which symptoms only occur after exercise is often missed with this test.
- Laboratories use different measuring methods; results from different labs cannot always be compared one to one.
How common is this
Wheat allergy is less common than gluten sensitivity; exact numbers for the Netherlands are not known. The allergy may be more common in children, who can also outgrow it. According to the Dutch medical specialists' guideline (FMS), food allergy in general occurs in 1 to 2 in 100 adults.
Who is this useful for
The result says the most when there has been a clear reaction shortly after eating wheat, as an addition to the conversation with the doctor. In people who eat wheat normally and have never had an acute reaction to it, a positive result does not mean you are allergic and can lead to avoiding wheat unnecessarily. With vague symptoms such as abdominal pain, tiredness or eczema without a clear link to a meal, the test adds little.
Downsides and risks
- A positive result without symptoms easily leads to wheat being left out of the diet unnecessarily. That can lead to a shortage of nutrients and, according to Thuisarts.nl, actually increase the chance of an allergy, especially in children.
- A normal result does not rule out symptoms caused by wheat: some people with symptoms have no IgE antibodies that 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