What your allergy test results mean

The immune system produces IgE antibodies to protect the body from parasitic infections.

In the case of an allergic reaction to a substance such as pollen, house dust mites or insect venom, the same mechanism is initiated. Your body produces IgE antibodies to fight off the substances it reacts to. These IgE antibodies activate mast cells, which in turn release histamine. The release of histamine leads to a dilation of blood vessels (allergy symptoms such as conjunctivitis, hives, edema) and the contraction of bronchial muscles (asthma symptoms).

If your body produces IgE antibodies against a certain allergen, it means you have sensitization for this allergen.

To understand what allergy tests like ALEX measure, it is important to understand the difference between sensitisation and allergy.

What does sensitisation mean?

Sensitisation is the first step towards developing an allergy. Allergic reactions do not occur upon first contact with an allergen. Before that can happen, your immune system must be able to recognise an allergen. When you get stung by a bee, your immune system will remember the structure of the allergen (= a protein in the insect venom) to be able to produce IgE antibodies against it in the future. This process is called sensitisation.

Sensitised but not allergic

In some people, IgE antibodies against a certain allergen have already formed. Still, when they get in contact/are exposed to the allergen source again, no allergy symptoms occur. In this case, a person has a sensitisation, but no allergy. Sometimes, a sensitisation of the immune system related to one (or more) allergens is present, but no allergy symptoms happen.

Sensitised and allergic

In other people, allergy symptoms will occur when they get in contact/are exposed to the allergen source again. In this case, a person has a sensitisation and an allergy. The immune system is sensitised to one or more allergens, and allergy symptoms occur because of it.

A sensitisation does not necessarily lead to symptoms, but without sensitisation, symptoms cannot occur.

The human immune system is unique and complex. As of now, we do not know the reason why some people are only sensitised, while others develop a full-on allergy.

What allergy test results show

Blood allergy tests screen for sensitisation to pre-selected allergens. Your test results will show your sensitisation status. Results indicating sensitisation do not necessarily mean that you are allergic, however. As explained above, it is possible that you are sensitised without allergy symptoms ever occurring.

For this reason, it is important to share your test results with a trained medical professional, even if you obtained your test results by using a home-testing kit. Only an allergy specialist can give an accurate diagnosis by looking at your test results, symptoms, and medical history, and suggest subsequent treatment if it is necessary.