Blood Count
Serum Iron — what it measures
For understanding, not diagnosis. Reference ranges differ between laboratories; the ranges on your own report, and your doctor’s reading of them, always come first.
What it measures
Serum iron measures the iron currently circulating in your blood attached to its transport protein. Unlike ferritin, which reflects stores, serum iron swings during the day and is usually interpreted with transferrin saturation and ferritin together.
What can skew it
Time of day, recent meals, iron supplements and inflammation can move serum iron substantially within hours.
Reference ranges
Reference ranges vary by laboratory, so serum iron should only be interpreted as part of the full iron panel, with your own report's ranges and your clinician.
Medical disclaimer: This page is educational only. It cannot tell you whether your result is normal or what to do about it — that is a decision for your doctor, with your full history.