Serum iron measures the iron circulating in blood bound to transferrin, the protein that carries it to the marrow and other tissues. It reflects what is in transit at the moment of the draw, not what the body has in store. For that reason it is one part of an iron panel rather than a standalone measure of iron status.
No readings for this marker yet.
Lowered values are most often seen with iron deficiency from blood loss, poor intake or poor absorption, and also during infection and inflammation, which pull iron out of circulation without any true shortage. Raised values most often follow iron supplements or transfusions, and can accompany conditions of iron overload or liver cell damage that releases stored iron. Because the figure swings widely from day to day, direction matters more than a single number, and interpretation rests on the panel as a whole. An unexpected result is a reason to re-test and speak with a doctor.
Iron follows a daily rhythm, running higher in the morning and falling through the day, so samples are usually taken in the morning after an overnight fast; oral iron, multivitamins and recent meals can raise it sharply for hours, and haemolysis of the sample falsely inflates it. It is interpreted together with ferritin, which reflects stores, and with transferrin, total iron binding capacity and transferrin saturation, the ratio that carries most of the diagnostic weight.
Reference ranges are general adult values and depend on lab, assay, age and sex. For orientation, not diagnosis — discuss results with your doctor.