What Is a Ferritin Blood Test For?

A ferritin blood test assesses your body's iron stores. It is the single most useful test for evaluating iron status.

Reasons for Testing

• Fatigue and weakness — rule out iron deficiency before anemia
• Heavy menstrual periods — monitor iron depletion
• Vegetarian/vegan diet — ensure adequate intake
• Chronic blood loss — GI bleeding
• Before/after iron supplementation — monitor response
• Hemochromatosis screening
• Athletic performance
• Pregnancy

Results Interpretation

• Below 12 ng/mL: depleted iron stores
• 12–20: low (may cause symptoms before anemia)
• 50–150: optimal functional range
• Above 300: inflammation, liver disease, or iron overload

Important

• Ferritin rises with inflammation regardless of iron stores
• Check CRP and transferrin saturation if inflammation suspected