Allergy and intolerance
IgE antilichamen berk
Antibodies against birch pollen; shows whether the immune system is sensitive to birch tree pollen, not whether it bothers you.
Everything about this testWhat it measures
The birch flowers in spring and then releases a lot of pollen. Pollen from related trees such as alder and hazel is similar to that of birch, so antibodies against birch often also fit symptoms caused by these trees. This test measures the amount of IgE antibodies against birch pollen in the blood, in kU/l. IgE is the type of antibody that, in an allergic reaction, triggers mast cells to release histamine; the body only makes these antibodies after it has previously been in contact with the allergen, and this is called sensitization.
- Sensitization to birch pollen: the body has made IgE antibodies against birch pollen
- Support in working out suspected hay fever from tree pollen, together with the history of the symptoms
- A possible explanation for itching or a burning feeling in the mouth after eating apple or nuts in people with hay fever
High
A value above the cut-off means that you have IgE antibodies against birch pollen: sensitization. That is not the same as an allergy. In people with symptoms such as sneezing, a blocked or runny nose, itchy or watery eyes or shortness of breath in spring, a positive result fits hay fever from tree pollen; according to Thuisarts.nl, this starts in February or March and is usually worst between March and the end of May. Some people with hay fever also get itching or a burning feeling in the mouth or throat when eating, for example, apple or hazelnut; the FMS guideline calls this oral allergy due to cross-reaction with pollen. In people without symptoms, a positive result only means that the antibodies are there; no treatment follows.
Low
A value below the cut-off means that no IgE antibodies against birch pollen were found. Hay fever from birch pollen is then much less likely. Symptoms later in the year more likely fit grass pollen (May to August) or weed pollen such as mugwort (late summer), and house dust mite, animals or mold can cause symptoms all year round. Nasal symptoms can also have a non-allergic cause.
If your result is abnormal
The GP mainly looks at the history: in which months and where the symptoms occur, and whether there are symptoms in the mouth after eating fruit or nuts. With a positive result and matching symptoms, advice follows to reduce contact with pollen, such as keeping windows closed on dry, sunny days, and if needed medication for the nose and eyes. With a lot of symptoms despite medication, an allergist or ENT specialist can discuss immunotherapy, where the result for single allergens helps determine which pollen it targets.
Reliability
A positive IgE result shows sensitization, not allergy: it only says that there are antibodies, not that you get symptoms from them. The Dutch medical specialists' guideline (FMS) on upper airway allergy says this literally and recommends choosing a test for single allergens based on the history of the symptoms; the result therefore only means something if it fits when and where you have symptoms. With birch pollen, spring is an important part of that history: symptoms that fit the flowering of trees make a positive result more meaningful. A positive result without symptoms is not treated.
Limitations
- Sensitization without symptoms is common; the result can only be interpreted together with the history of the symptoms.
- Birch pollen cross-reacts with pollen from alder, hazel and other trees; the test does not show exactly which tree you react to.
- Antibodies against birch pollen often also give a positive IgE result for nuts, fruit or soy without a real food allergy.
- Laboratories use different measurement methods and cut-off values; results from different labs cannot be compared one to one.
How common is this
Hay fever is common and often starts at a young age. According to the Longfonds (Dutch lung foundation), trees such as hazel, alder and birch cause symptoms from January to May. Sensitization is more common than the allergy itself.
Who is this useful for
Useful with symptoms of the nose, eyes or airways that come back every year in spring, especially outdoors on dry, sunny days, and with itching in the mouth or throat after eating apple or nuts in someone with hay fever. In people without such symptoms, the test adds nothing: sensitization without symptoms is not a disease and is not treated.
Downsides and risks
- A positive result, together with positive results for nuts or fruit due to cross-reaction, can lead to unnecessarily avoiding foods that you eat without severe symptoms.
- A normal result does not rule out symptoms in spring from other trees or other causes.
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