Is Eisen-Ferritin Selbsttest useful for fatigue?

An iron/ferritin self-test may provide a preliminary clue for iron deficiency as a cause of fatigue, but it has significant limitations. Ferritin is an acute-phase reactant; inflammation, infection, or chronic disease can elevate ferritin levels even when iron stores are low, leading to false reassurance. Conversely, low ferritin does not always explain fatigue—other causes like thyroid dysfunction, vitamin D or B12 deficiency, sleep disorders, or depression are common. The evidence supporting self-testing for fatigue is weak: no robust studies show improved outcomes compared to clinical evaluation. A physician can interpret ferritin alongside transferrin saturation, CRP, and complete blood count, and rule out underlying conditions. Self-testing without medical guidance risks misinterpretation and unnecessary supplementation. For persistent fatigue, a clinical workup is recommended. The test may be a starting point but is not a diagnostic tool. Evidence: practice/unclear.