Total IgE
A blood measure of overall allergic tendency. It reflects how 'atopic' a person is — often raised in allergies, asthma and eczema, and markedly so with parasitic infection — but it does not identify which specific allergy someone has.
What it measures
Immunoglobulin E (IgE) is the antibody class at the centre of allergic reactions and the defence against parasitic worms. Total IgE measures all of it in the blood, giving a broad sense of a person's allergic (atopic) tendency rather than a specific answer. It is often raised in people with allergic conditions — hay fever, asthma, eczema, food allergy — and can be very high with parasitic infection or in rare immune conditions. Its key limitation is that it is non-specific: a normal total IgE does not exclude a specific allergy, and a raised one does not say what the person is allergic to. To identify a particular trigger, allergen-specific IgE tests (or skin-prick testing) are used instead. Total IgE is most useful as background context, and in a few specific situations such as dosing certain allergy or asthma treatments.
What a high value can mean
- Allergic (atopic) conditions — hay fever, asthma, eczema, food allergy; commonly raised.
- Parasitic (worm) infections — often markedly high, especially with relevant travel.
- Atopic dermatitis (eczema) — can be very high.
- Allergic bronchopulmonary aspergillosis — a specific lung allergy with very high IgE.
- Rare immune disorders (hyper-IgE syndrome) — extremely high levels.
- Smoking — modestly raises IgE.
What a low value can mean
- Normal or low — reduces but does not exclude a specific allergy; many people with a single specific allergy have a normal total IgE.
- Rarely — a low IgE with recurrent infection can be part of an immune deficiency.
When to discuss with a doctor
Total IgE is best understood as a background measure of allergic tendency, not a test that pins down an allergy. A raised total IgE fits an atopic picture (allergies, asthma, eczema) or, with the right history, prompts thought about parasites — but it does not tell you the trigger. When identifying a specific allergen matters, allergen-specific IgE or skin-prick testing is the right test. Total IgE has particular uses in specialist settings, such as guiding the dose of certain biologic treatments for severe allergic asthma or eczema. Mediora.AI shows total IgE alongside the eosinophil count as part of the allergic picture; specific allergy testing and treatment belong with your doctor or an allergist.