Is Eisen-Ferritin Selbsttest useful for Sport?

The question of whether an iron-ferritin self-test is useful for sports is legitimate, but the answer requires a nuanced view. Ferritin is a storage protein for iron and a key biomarker of the body's iron supply. In athletes, especially endurance athletes, iron deficiency can impair performance because iron is essential for oxygen transport (hemoglobin) and mitochondrial energy production. A self-test could theoretically help detect low ferritin early. However, there are several limitations: measuring ferritin alone without other iron parameters (e.g., transferrin saturation, soluble transferrin receptor) can be misleading, as ferritin also rises as an acute-phase reactant during inflammation. Moreover, standardized reference ranges for athletes are lacking; a value in the lower normal range may already be suboptimal for an athlete. The accuracy of home tests is often lower than laboratory methods, and interpretation requires medical expertise. Therefore, the utility for sports is limited unless the test is used in consultation with a physician or sports medicine specialist and supplemented by further diagnostics. Without clinical context, there is a risk of misinterpretation and unnecessary supplementation. Evidence: human-observational.