What this marker measures
Serum iron alone is a relatively poor diagnostic marker because it fluctuates throughout the day and is affected by recent meals, exercise, and illness. It is most useful as part of a complete iron panel (serum iron, TIBC, transferrin saturation, ferritin).
High or low: what it can mean
High Iron
Elevated serum iron can reflect iron overload (hemochromatosis), acute hepatitis (iron release from damaged liver cells), or excessive iron supplementation.
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Low Iron
Low serum iron is common in iron deficiency but also occurs in inflammation (as iron is redistributed to storage sites). Interpreting serum iron alongside ferritin and transferrin saturation gives the clearest picture.
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Frequently asked questions
What is Iron?
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Serum iron measures the amount of iron circulating bound to transferrin in the blood. It represents iron in transit between storage and use, not total body iron stores.
What does Iron measure?
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Serum iron alone is a relatively poor diagnostic marker because it fluctuates throughout the day and is affected by recent meals, exercise, and illness. It is most useful as part of a complete iron panel (serum iron, TIBC, transferrin saturation, ferritin).
What does high Iron mean?
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Elevated serum iron can reflect iron overload (hemochromatosis), acute hepatitis (iron release from damaged liver cells), or excessive iron supplementation.
What does low Iron mean?
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Low serum iron is common in iron deficiency but also occurs in inflammation (as iron is redistributed to storage sites). Interpreting serum iron alongside ferritin and transferrin saturation gives the clearest picture.
Related biomarkers
Editorial note
LabTestly explains lab markers using plain-English educational content. Reference ranges may vary by laboratory and should be interpreted with a clinician.
Educational content · Editorially reviewed for clarity · Last updated
Common sources used for lab-test education
Not medical advice
This page is for general understanding only and does not replace medical advice from your clinician. Reference ranges can vary by laboratory, age, sex, pregnancy status, medications, and clinical context.