Evidence check: Ferritin Eisenmangel in the context of fatigue

Ferritin is the main iron storage protein and a key marker of iron status. Low ferritin (<30 µg/L) indicates iron deficiency, which can cause fatigue even without anemia (normal hemoglobin). The evidence is moderate: several RCTs show that iron supplementation improves fatigue in iron-deficient non-anemic women. However, ferritin is an acute-phase reactant; inflammation, infection, or liver disease can falsely elevate levels. A DNA test alone cannot diagnose iron deficiency – clinical measurement of ferritin, hemoglobin, transferrin saturation, and CRP is required. Caution: iron overload is toxic; supplementation should only be done under medical supervision. The provided context lacks specific ferritin data, so this answer is based on general medical evidence.