Allergy and intolerance
IgE antilichamen kat
Antibodies against cat allergen; shows whether the immune system is sensitive to cats, not whether you get symptoms from them.
Everything about this testWhat it measures
Cats spread allergens through their dander and saliva. The dander floats through the air, sticks to furniture and clothing and, according to Thuisarts.nl, can stay in a home for half a year after a cat has gone. This test measures the amount of IgE antibodies against cat dander 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 cats: the body has made IgE antibodies against cat allergen
- Support in working out a suspected cat allergy, together with the history of the symptoms
- A starting point with symptoms that occur at home or on visits near a cat
High
A value above the cut-off means that you have IgE antibodies against cat allergen: sensitization. That is not the same as an allergy. In people who get symptoms near a cat, such as sneezing, a blocked or runny nose, itchy or watery eyes or shortness of breath, a positive result fits a cat allergy. Even people without a cat of their own can get symptoms in homes where a cat lives or has lived. In people without such 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 cat allergen were found. A cat allergy through IgE is then much less likely. Symptoms at home or around animals can also have other causes: an allergy to another animal, to house dust mite or to mold, or non-allergic rhinitis from irritants such as smoke and odors.
If your result is abnormal
The GP mainly looks at the history: when and where the symptoms occur. With a positive result and matching symptoms, the main advice is to stay away from cats as much as possible; sometimes a new home for a pet is needed, and according to Thuisarts.nl symptoms can then last for months because dander stays in the home. If needed, medication for the nose, eyes or airways follows, and with symptoms that are not controlled this way, referral to an ENT specialist, lung specialist or allergist may follow.
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. Sensitization to cats also occurs in people who never have trouble with cats; in them 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 history of the symptoms.
- The test measures all cat allergens together; testing single proteins (components) can say more in case of doubt, for example about cross-reaction with other animals.
- The result says little about the severity of the symptoms; a higher value does not automatically mean more trouble.
- Laboratories use different measurement methods and cut-off values; results from different labs cannot be compared one to one.
How common is this
Allergy to pet dander, such as from cats, is, alongside pollen and house dust mite, a known cause of allergic nose and eye symptoms, and can make asthma worse. Sensitization is more common than the allergy itself: some people with antibodies have no symptoms at all.
Who is this useful for
Useful with symptoms that occur near cats or in homes where a cat lives: sneezing, a blocked or runny nose, itchy or watery eyes, coughing or shortness of breath. The result then helps determine whether limiting contact with cats makes sense. 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 can lead to giving away a pet unnecessarily, while sensitization without symptoms does not need treatment.
- A normal result does not rule out symptoms at home; house dust mite, other animals, mold and non-allergic causes also cause nasal symptoms.
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