Ferritin Reference Ranges and Clinical Thresholds

Normal Reference Intervals

The lower limit of normal reported by most laboratories is 15–30 ng/mL, but this range may not correspond to optimal body iron stores. 1
In adult women, average ferritin concentrations are about 43 ng/mL according to CDC‑based guidance. 1
The reduced ferritin levels observed in young women are primarily attributable to menstrual blood loss, which drives iron deficiency in this population. 1

A ferritin concentration < 15 ng/mL provides 100 % specificity for absent bone‑marrow iron stores in women of child‑bearing age. 1
Ferritin < 30 ng/mL generally indicates low body iron stores and demonstrates high sensitivity and specificity for diagnosing iron deficiency in adults. 1
In adolescent females, a ferritin level of 10 ng/mL definitively confirms depleted iron stores. 1
Several studies define iron deficiency as serum ferritin ≤ 15 µg/L. (Evidence from the American Journal of Clinical Dermatology, 2017.) 2, 3, 4, 5

During therapeutic phlebotomy for hereditary hemochromatosis, the target ferritin is 50 µg/L in the induction phase and 50–100 µg/L for maintenance therapy. (Guideline from the Journal of Hepatology, 2022.) 6

Ferritin is an acute‑phase reactant; infections, inflammation, or tissue injury can falsely raise ferritin levels independent of true iron status. 1
In the presence of inflammation, a ferritin value < 45 ng/mL still suggests iron deficiency with 92 % specificity. 1
When inflammatory conditions are suspected, measuring C‑reactive protein (CRP) alongside ferritin is recommended to improve interpretation. 1

For adolescent females with iron deficiency, therapeutic goals should raise ferritin to at least 20–30 ng/mL (minimum target) and preferably 30–50 ng/mL to achieve optimal iron stores. 1