Nutrients
Serum iron
Fe
Included in Baseline and Complete.
Compare membershipsA snapshot of the iron moving through your blood.
Serum iron measures the iron circulating in your blood, mostly carried by a protein called transferrin. Iron helps red blood cells carry oxygen, and this result is most useful when read with ferritin and transferrin saturation.
Serum iron changes from hour to hour.
Your blood iron shifts through the day, tends to be higher in the morning, and can rise after a meal or an iron supplement. That's why a morning draw, ideally fasting, gives the most comparable result, and why serum iron on its own says little about your iron stores.
Low serum iron can reflect iron deficiency, and it can also drop during inflammation or infection. High serum iron can point to iron overload, recent supplements, or some liver conditions.
Ferritin shows the savings account. Serum iron shows today's cash flow.
Questions
Why is serum iron tested with other iron markers?
Serum iron changes quickly, so it's hard to interpret alone. Read together with ferritin, TIBC, and transferrin saturation, it helps show whether your iron stores, transport, and supply line up, which gives a much clearer picture of your iron status.
Do supplements or medicines affect my result?
Yes. A recent iron supplement or meal can raise serum iron for a time. Birth control pills, estrogens, testosterone, and some other medicines can also affect the result, so tell your clinician what you take.