Ferritin
What it measures, and what changes the number.
Ferritin is the protein that stores iron inside cells, and the small amount found in blood reflects the size of the body's iron stores. The test measures ferritin in serum or plasma by immunoassay.
It is usually ordered as part of an iron panel with serum iron, transferrin or TIBC and transferrin saturation, which together describe both stored iron and iron in circulation. Ferritin is also an acute phase protein that rises with inflammation, infection and liver injury, so CRP is often measured at the same time to help put it in context.
Ferritin is more stable than serum iron and is less affected by time of day or a recent meal, though iron panels are often drawn in the morning because serum iron varies. Different assays can give different values, so trends are easiest to follow within one lab. Labs may print it as Ferritina.
Reference ranges labs publish
Each lab states an interval for its own method and the population it measured. They differ, they are not interchangeable, and none of them is a verdict on a single result.
- Men, 18 years and over: 31 to 409 mcg/L · ECLIA (immunoassay) · Source: Mayo Clinic Laboratories, FERR1 (Ferritin, Serum) (read 2026-09-24)
- Men, adults: 30 to 400 ng/mL · ECLIA (immunoassay) · Source: Labcorp, 004598 (Ferritin) (read 2026-09-24)
- Women, 18 to 50 years: 6 to 175 mcg/L · ECLIA (immunoassay) · Source: Mayo Clinic Laboratories, FERR1 (Ferritin, Serum) (read 2026-09-24)
- Women, 51 years and over: 11 to 328 mcg/L · ECLIA (immunoassay) · Source: Mayo Clinic Laboratories, FERR1 (Ferritin, Serum) (read 2026-09-24)
- Women, adults: 15 to 150 ng/mL · ECLIA (immunoassay) · Source: Labcorp, 004598 (Ferritin) (read 2026-09-24)
Often read alongside: Iron, Transferrin saturation, TIBC, Transferrin, CRP