Iron
Serum Iron
- Sample
- Blood
- Usual units
- µg/dL
Also known as Serum Iron · S. Iron · Fe
What this test measures
Iron is a mineral the body uses to build hemoglobin and a number of enzymes, and most of the body's iron is held inside red blood cells rather than free in the bloodstream. A serum iron test measures the iron circulating in blood, bound mainly to the carrier protein transferrin, giving a picture of iron currently in transit rather than iron in storage. It is usually reported in micrograms per deciliter (µg/dL).
Reading your report
There isn’t one standard range for this test — each lab prints its own. Use the range shown next to your result.
Iron unit converter
Convert Iron units
Labs print this test in µg/dL or µmol/L depending on where the sample was run.
Related guides
- Guide
Why the same blood test has different "normal" ranges at different labs
Reference intervals are built from each lab's own population and equipment, which is why two labs can print different ranges for the same sample.
- Guide
Reference interval, cutoff, and the "optimal" numbers online: three different things
The range beside your result, the target a website quotes, and the threshold that defines a condition are built in different ways and answer different questions.
- Guide
Why the same lab printed a different reference range for you this year
Ranges are not fixed constants. The lab can change method, revise its reference group, or apply a range that depends on your age — none of which is an error.
- Guide
Ferritin, serum iron, TIBC and transferrin saturation: four views of iron
An iron panel measures iron in circulation, iron in storage, and the capacity to carry it — plus a percentage computed from two of them.