Ferritin

What it measures

Measures the main iron storage protein; its level in blood reflects body iron stores. It is the most useful single test for iron deficiency and for monitoring iron overload.

Specimen and preparation

• Specimen: Serum or lithium-heparin plasma
• Tube: Gold top
• Preparation: No fasting needed. Avoid testing during acute illness if possible.

Reference range

Reference ranges differ between laboratories, methods and populations. Always use the range printed on your own lab report.

Causes of high values

• Inflammation, infection or malignancy (acute-phase protein)
• Hemochromatosis and transfusional iron overload
• Liver disease, alcohol
• Hemophagocytic lymphohistiocytosis (very high)
• Metabolic syndrome

Causes of low values

• Iron deficiency (diagnostic when below about 15–30 ng/mL)

Method

Immunoassay (chemiluminescence, immunoturbidimetry or ELISA)

Good to know

ng/mL equals µg/L. Because ferritin rises in inflammation, a normal value does not exclude iron deficiency; values under about 100 ng/mL with inflammation may still indicate deficiency.

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