Allergy and intolerance
Schimmelmengsel (IgE)
One IgE test for 4 common molds together; shows whether you are sensitized to molds, not to which mold.
Everything about this testWhat it measures
The test measures, in one go, IgE antibodies against a fixed mix of 4 molds: Penicillium chrysogenum, Cladosporium herbarum, Aspergillus fumigatus and Alternaria alternata. Cladosporium and Alternaria are mainly found in outdoor air, with the most spores in summer and late summer; Penicillium and Aspergillus more often grow indoors in damp places and in compost, hay or potting soil. 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 an allergen, and this is called sensitization. Because the 4 molds are tested together, the result gives one number and a verdict of positive or negative, but not which mold the antibodies are directed against. Yeasts such as Candida are not in the mix.
- Sensitization to at least one of the 4 molds in the mix: the body has made IgE antibodies against one or more of them
- An indication of whether symptoms of the nose, eyes or airways may be caused by molds, outdoors in summer and late summer or in a damp home
Positive
A positive result means that you have IgE antibodies against at least one of the molds in the mix: sensitization. That is not the same as an allergy, and the test does not say which mold the antibodies are directed against. In people with nose or eye symptoms, coughing or shortness of breath in summer and late summer, in a damp home or when working with plants, hay or compost, a positive result can fit a mold allergy. According to Thuisarts.nl, molds can cause nasal symptoms all year round. In people without such symptoms, a positive result only means that the antibodies are there; no treatment follows.
Negative
A negative result means that no IgE antibodies against the 4 molds were found. An allergy to these molds is then less likely, but an allergy to other molds is not ruled out. Symptoms in summer can also come from pollen, and symptoms in a damp home from house dust mite or 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 advice is mainly about limiting contact with molds, for example by tackling damp and mold patches at home and ventilating well, and if needed a test for single molds follows. With poorly controlled asthma, especially with sensitization to Aspergillus fumigatus, referral to a lung specialist 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 recommends choosing an IgE test for single allergens based on the history of the symptoms; a mix tests more allergens at the same time, so a low sensitization without clinical meaning can more easily make the result positive. With molds, the result is harder to interpret than with pollen or house dust mite: there are many kinds of mold and the symptoms are less clearly linked to one season or one place. The mix is mainly a first step: a negative result makes an allergy to these 4 molds less likely, a positive result can be looked into further with a test for single molds.
Limitations
- Sensitization without symptoms is common; the result can only be interpreted together with the history of the symptoms.
- The test does not say which mold you react to; that requires a test for single molds.
- Other molds and yeasts are not measured.
- Laboratories use different mixes, measurement methods and cut-off values; results from different labs cannot be compared one to one.
How common is this
Molds are, alongside pollen, house dust mite and pets, a known cause of allergic nasal symptoms. Mold allergy is less common than allergy to pollen or house dust mite. Sensitization is more common than the allergy itself.
Who is this useful for
Useful with nose or eye symptoms, coughing or shortness of breath that fit molds: outdoors in summer and late summer, when working with plants, hay or compost, or in a home with damp and mold patches. In people with asthma, the result can help recognize molds as a trigger. 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 unnecessary worry about mold at home, while sensitization without symptoms does not need treatment.
- A negative result does not rule out an allergy to other molds.
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