Lay opinion vs evidence: Ferritin Frauen

Lay opinion often states: 'Low ferritin = iron deficiency → take iron supplements.' The evidence is more nuanced. Ferritin is an acute-phase reactant; it can be falsely elevated during inflammation (CRP >5 mg/L), masking true iron deficiency. Conversely, women with heavy menstrual bleeding may have genuinely low ferritin without anemia. The DGE recommends 10–15 mg iron/day for women; EFSA sets a safe upper limit of 40 mg/day. A single ferritin value from a home test is not diagnostic; a full iron panel (serum iron, transferrin, transferrin saturation, ferritin) plus CRP is needed. Supplementing without medical workup risks iron overload in individuals with undiagnosed hemochromatosis. Evidence is 'human-moderate': associations are well-established, but individual interpretation requires clinical context.