Allergy and intolerance
Huisstofmijt specifiek IgE
Antibodies against house dust mite; shows whether the immune system is sensitive to house dust mite, not whether it gives you symptoms.
Everything about this testWhat it measures
The house dust mite is a tiny creature that lives in mattresses, duvets, carpets and cuddly toys and feeds on skin flakes. It is not the mite itself but the proteins in its droppings that cause the symptoms. This test measures the amount of IgE antibodies in the blood against those proteins of Dermatophagoides pteronyssinus, the house dust mite most common in Dutch homes, in kU/l. There is a separate test for the other common species, D. farinae. 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, and this is called sensitization.
- Sensitization to house dust mite: the body has made IgE antibodies against house dust mite
- Support in investigating a suspected house dust mite allergy, together with the story of the symptoms
- A starting point in assessing symptoms that are present all year round, such as a blocked nose, sneezing or shortness of breath
High
A value above the cutoff means that you have IgE antibodies against house dust mite: sensitization. This is not the same as an allergy. In people with symptoms that are present all year round, such as a blocked or runny nose, sneezing, itchy eyes or shortness of breath indoors, a positive result fits a house dust mite allergy. In people without such symptoms, a positive result only means that the antibodies are there; no treatment follows then. The level of the value says little about how severe the symptoms are.
Low
A value below the cutoff means that no IgE antibodies against house dust mite have been found. An IgE-mediated house dust mite allergy is then a lot less likely. Symptoms that are present all year round can also have other causes: an allergy to pets or molds, a non-allergic inflammation of the nose, irritants such as smoke and odors, or chronic sinusitis.
If your result is abnormal
The GP mainly looks at the story: when the symptoms occur, where they get worse and whether there is also asthma or eczema. With a positive result and matching symptoms, advice follows on reducing contact with house dust mite and, if needed, medicines for the nose or airways. If the symptoms are not brought under control with this, a referral to an ENT specialist, lung specialist or allergist may follow, where allergen immunotherapy may also be discussed.
Reliability
A positive IgE result shows sensitization, not allergy: it only says that there are antibodies, not that they give you symptoms. The Dutch medical specialists' guideline (FMS) on upper airway allergy states this literally; the result is therefore only meaningful if it fits the story of the symptoms. Sensitization to house dust mite is common in people without symptoms, so in them the predictive value is low and a positive result is often not the explanation for anything. A positive result without symptoms is not treated.
Limitations
- Sensitization without symptoms is common; the result can only be interpreted together with the story of the symptoms.
- The test measures all house dust mite proteins together; testing for individual proteins (components) can distinguish between a true house dust mite allergy and a cross-reaction, for example with shellfish or snails.
- The result says little about the severity of the symptoms; a higher value does not automatically mean more trouble.
- Laboratories use different measuring methods and cutoff values; results from different labs cannot be compared one to one.
How common is this
House dust mite allergy is one of the most common allergies in the Netherlands and causes symptoms that are present all year round. Sensitization is even more common than the allergy itself: some people with antibodies have no trouble from them at all. The symptoms often start in childhood and regularly go together with asthma or eczema.
Who is this useful for
Useful with symptoms that are present all year round and are worse indoors: a blocked or runny nose, sneezing in the morning, itchy eyes, coughing or shortness of breath, especially in bed or when dusting and tidying. The result then helps to decide whether measures against house dust mite are worthwhile. 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 without symptoms easily leads to unnecessary measures at home, such as replacing the mattress, bedding or carpeting, while sensitization without symptoms does not need to be treated.
- A normal result does not rule out symptoms caused by the bedroom or the house; there are also non-allergic causes of a blocked nose.
Sources
- NVKC, allesovertesten.nl: Allergie (RAST)
- FMS Richtlijnendatabase: Allergie van de bovenste luchtwegen, module Aanvullende diagnostiek
- FMS Richtlijnendatabase: Allergie van de bovenste luchtwegen, module Klinische diagnostiek
- Thuisarts.nl: Ik wil iets doen tegen huisstofmijt
- Thuisarts.nl: Ik heb allergie
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