Ferritin Test

Ferritin is a protein that stores iron inside your cells, and measuring its level in the blood is currently the single most sensitive and reliable way to assess your body's total iron reserves.

Unlike serum iron, which fluctuates significantly with diet and time of day, ferritin levels remain relatively stable and reflect the amount of iron actually stored in tissues like the liver, spleen, and bone marrow.

A low ferritin level is one of the earliest indicators of developing iron deficiency, often appearing before hemoglobin itself drops low enough to be classified as anemia, which makes ferritin a valuable early-warning test.

On the other end of the spectrum, ferritin also rises during inflammation and certain iron overload conditions, so it needs to be interpreted carefully alongside other clinical information.