Allergy and intolerance
IgE antilichamen rat
Antibodies against rat allergen from skin, urine and blood; shows whether you are sensitized to rats, not whether you get symptoms.
Everything about this testWhat it measures
Rats spread a large part of their allergens through their urine; it gets into the bedding and then into the air as dust. Allergens are also found in dander, hair and saliva. This test measures the amount of IgE antibodies in the blood against a mix of skin cells (epithelium) and blood and urine proteins of rats, in kU/l. The body only makes these antibodies after it has previously been in contact with the allergen; this is called sensitization.
- Sensitization to rats: the body has made IgE antibodies against rat allergens
- A lead with symptoms when working with laboratory animals or when keeping rats as pets
High
A value above the cut-off means that you have IgE antibodies against rat allergens: sensitization. That is not the same as an allergy. In people who get symptoms when working with rats, for example in a laboratory or animal research facility, or with rats at home, such as sneezing, a blocked or runny nose, itchy or watery eyes, hives or shortness of breath, a positive result fits an allergy to rats. Rat and mouse allergens are partly similar, so the results are often positive together. In rare cases, contact with rats, for example a bite, can cause a severe allergic reaction (anaphylaxis) in someone with this allergy. 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 this allergen were found. An IgE-mediated allergy to this allergen is then much less likely, although it is not completely ruled out. Symptoms can also come from another allergen that was not tested, or have a non-allergic cause.
If your result is abnormal
The GP mainly looks at the history: with which animal and in which situation the symptoms occur, and whether they get better on days off and during holidays. With an allergy, the most important advice is to limit contact with rats; with symptoms caused by work, the occupational health doctor can look at measures at work to reduce contact with the allergens. With asthma or symptoms that are not brought under control with medication, a referral to a 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; for food allergy, the FMS guideline on food challenge testing calls the history of the symptoms the cornerstone of diagnosis and a food challenge in hospital the gold standard. The result therefore only means something if it fits when, where and after contact with what you get symptoms. 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.
- Related allergens can recognize each other's antibodies (cross-reaction), for example pollen and nuts or fruit; a positive result then does not mean that this particular allergen causes the symptoms.
- The test measures all proteins from the allergen source together; testing for individual proteins (components) can say more in case of doubt.
- 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 rats and mice is a known occupational risk for people who work with laboratory animals; the Dutch medical specialists' guideline (FMS) on work-related asthma lists allergens from (laboratory) animals as a cause of asthma from work. According to a 2026 review, between 4.4 and 30 in 100 people who work with rats or mice in a laboratory have such an allergy. Outside work, it mainly concerns people who keep rats as pets.
Who is this useful for
Useful with symptoms of the nose, eyes, skin or airways that occur when working with rats, such as in a laboratory, animal research facility or pet shop, or with rats as pets. If you also work with mice, it is best to do this test together with the one for mouse. In people without such symptoms, the test adds nothing: sensitization without symptoms is not a disease and is not treated.
Sources
- NVKC, allesovertesten.nl: Allergie (RAST)
- FMS Richtlijnendatabase: Allergie van de bovenste luchtwegen, module Aanvullende diagnostiek
- FMS Richtlijnendatabase: Voedselprovocatie, module Plaatsbepaling diagnostiek voedselallergie
- Thuisarts.nl: Ik heb allergie
- Caron J, Lemoine A, Herman A, et al. Occupational allergy to rat and mouse in research laboratories. Curr Allergy Asthma Rep 2026;26:6
- Kampitak T, Betschel SD. Anaphylaxis in laboratory workers because of rodent handling: two case reports. J Occup Health 2016;58:381-383
- FMS Richtlijnendatabase: Werkgerelateerd astma, module Diagnostiek
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