Iron (Serum Iron)
Also known as: Serum iron, Fe
Serum iron measures the amount of iron circulating in your blood at the time of the test. Iron is essential for carrying oxygen in your red blood cells.
Why it's measured
Iron is usually measured as part of a group of “iron studies” that together give a clearer picture than any single value. Levels can vary through the day and with recent meals or supplements.
Typical range
Reference ranges vary by lab and the time of day the sample was taken. Because a single iron value can fluctuate, doctors interpret it alongside ferritin and other iron studies.
What high values can mean
Higher serum iron is one value doctors consider together with the rest of the iron studies, rather than in isolation.
What low values can mean
Lower serum iron is another value read in the context of the full iron panel and your symptoms.
Questions to ask your doctor
- How does my iron fit with my ferritin and other iron studies?
- Could the timing of the test or supplements have affected it?
- Is any follow-up testing helpful here?
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Try the explainerEducational information only — not medical advice, diagnosis, or treatment. Reference ranges vary by lab; always use your own lab's range and discuss results with a qualified clinician.