Evidence check: IgE Allergietest in the context of fatigue

An IgE allergy test measures specific antibodies to allergens and can indicate allergic sensitization. In the context of fatigue, the evidence is limited: allergies may contribute to fatigue through inflammatory pathways, histamine release, or sleep disruption (e.g., in allergic rhinitis), but this is only one possible factor among many. Most causes of fatigue are non-allergic (iron deficiency, thyroid dysfunction, sleep apnea, psychological stress). A positive IgE test alone does not explain fatigue and can lead to misinterpretation, as many people are sensitized without symptoms. Consumer tests like MyBody-X are not medical diagnostics and in Germany are regulated under GenDG, which prohibits disease claims. The evidence for using an IgE test in fatigue workup is 'mixed': mechanistic links exist, but no robust clinical trials support routine use. A medical evaluation with history and appropriate testing is recommended.