Immunoglobulins E (IgE) are antibodies that reveal an allergy or an atopic condition. Why and how to do an IgE assay? How to interpret the results?
What is the role of IgE?
Immunoglobulin E (IgE) are antibodies produced by B lymphocytes, a type of white blood cell, in the event of a reaction to an allergen. We distinguish the Total IgE which testify to a global atopic terrain, and specific IgE, which are directed against an allergen especially. “The role of IgE is to respond to the intrusion of abnormal elements such as allergens and which will trigger an allergic reaction in the body. They also intervene in pest control“, explains Gaël Saintenoy, biologist.
What is the normal IgE level?
The total IgE level should be less than 150 IU/ml (International Units per millilitre). A higher value may indicate an allergy or an allergic condition, a parasitic infection, or any other cause that must be ruled out by your doctor. Values may vary from lab to lab. “Nevertheless, you should know that the total IgE assay is used less and less, whatever the context, parasitic or allergic. The use of specific IgE is much more indicated“, nuances the biologist.
Why measure IgE?
An IgE assay is prescribed in case of suspected parasitic infection or allergy. It also allows to differentiate between atopic and non-atopic diseases. “It is possible to measure total IgE for measure the overall level of IgE in the blood. The priority in case of suspected allergy is to measure specific IgE, in association with skin tests to assess sensitivity to particular allergens. Diagnosis is often made by an allergist who will use this clinico-biological arsenal to arrive at his diagnosis”details the specialist.
In case of allergy?
Allergy is the main indication to perform an IgE assay total and/or specific.
The IgE assay consists of a blood sample taken from the bend of the elbow. To obtain the precise dosage of specific IgE, the blood is brought into contact with the suspected allergen.
What does a high IgE level mean?
A high level of total IgE or specific IgE means that there is a possibly allergic or parasitic response.
What symptoms?
A high level of IgE can cause the classic symptoms of an allergy: runny nose, sneezing, watery eyes, coughing and respiratory discomfort in case of air allergy. In the case of a food allergy, the symptoms generally appear within two hours of ingesting the allergenic food. May occur: rhinitis, an outbreak of eczema, hives, digestive disorders such as nausea and vomiting, gastroesophageal reflux or even angioedema.
What does low IgE mean?
“A low total IgE level means that it is unlikely that the patient has an allergy or infection parasitic“, reassures the biologist.
What symptoms?
A low IgE level does not cause no symptoms since it is not indicative of an allergy.
What to do in case of abnormal IgE levels?
An abnormal IgE level requires consult an allergist. The treatment is carried out in two stages. It includes treatment medication to relieve allergy symptoms : antihistamines, corticosteroids or even adrenaline by injection in case of anaphylactic shock. Nose washes should be daily to reduce the symptoms of allergic rhinitis. And the treatment of the cause of the allergy which is based on the removal of the allergen when possible or at the desensitization to stimulate the patient’s immune system and gradually make it tolerant to the substance in question.
Thanks to Gaël Saintenoy, biologist.