Positive respiratory allergy blood screen: which allergen still needs identifying?

A laboratory result must not delay care for current breathing difficulty. New breathlessness without distress needs medical advice the same day. In France, call 15 or 112 immediately if it prevents you from finishing sentences or comes with bluish lips or changes in alertness.

Some blood screens for respiratory allergy use a mixture of allergens that are not tested separately. They look for IgE antibodies directed against one or more ingredients of that mixture. Before interpreting a positive result, ask your doctor which exact type of test was performed.

With this type of test, a positive result is combined: it does not by itself identify the precise allergen. Assurance Maladie says that further allergy investigation is needed. The report is therefore a starting point for discussion, rather than a confirmed list of exposures responsible for symptoms.

The doctor asks about the circumstances of symptoms, their frequency and their timing after possible contact. For nasal symptoms, this may include whether they occur around dust or an animal. Describe what you observed without deciding yourself which substance caused the reaction.

Depending on the assessment, the allergist may choose skin tests or blood measurement of IgE specific to selected allergens. Skin tests examine the skin's reaction to small quantities of allergens. Blood testing can be used, for example, when skin tests are not possible or are inconclusive.

Results need to be considered alongside clinical symptoms. For some tests examining allergens separately, Ameli explains that a positive result can occur without allergy symptoms. Ask what has been established, which allergen still needs identifying and what medical step is proposed before changing your environment.