Evidence check: AllergieCheck | IgE-Antikörper Test in the context of fatigue

The Allergy Check (IgE antibody test) measures specific or total IgE levels, which can be elevated in allergic conditions. In the context of fatigue, the evidence is weak: allergies may indirectly contribute to fatigue (e.g., via sleep disruption in allergic rhinitis or systemic inflammation), but an IgE test alone is not a diagnostic tool for fatigue. Most fatigue causes are non-allergic (iron deficiency, thyroid dysfunction, sleep apnea, psychological factors). The test is often marketed as part of exaggerated 'functional medicine' diagnostics without randomized trials showing clear benefit. Caveat: Elevated IgE can also occur with parasites, autoimmune diseases, or without clinical relevance. A negative test does not rule out allergies as a fatigue contributor. Evidence rating: unclear/marketing, as the link between IgE and fatigue is insufficiently supported.