Ferritin is one of the most important and most underutilized blood tests in pediatric medicine. Unlike hemoglobin, which only falls once anemia is established, ferritin begins declining as soon as iron stores are depleted. It is the earliest and most sensitive marker of iron deficiency.
What Is Ferritin?
Ferritin is an intracellular protein that stores iron and releases it as needed. The ferritin level in blood reflects total iron stores throughout the body. Low ferritin means iron stores are depleted, even if hemoglobin is still normal.
Normal Ferritin Ranges for Children
Reference ranges vary by age and laboratory: – Newborns: 25–200 ng/mL – 1–5 months: 50–200 ng/mL – 6 months–12 years: 7–140 ng/mL – Adolescents: 12–150 ng/mL (lower threshold for girls post-puberty)
Iron deficiency is generally diagnosed when ferritin falls below 12–15 ng/mL. Many researchers use a more conservative threshold of 20–30 ng/mL for optimal cognitive and developmental support.
The Ferritin Trap: Inflammation
Ferritin is an acute-phase reactant, it rises during any infection or inflammatory process, even when iron stores are low. This means a child with iron deficiency who is also sick may show a falsely normal ferritin.
Always interpret ferritin alongside a C-reactive protein (CRP). If inflammation markers are elevated, a low-normal ferritin may still represent true iron deficiency.
When to Test
- At 12-month well-child visit (universal AAP recommendation)
- Any time symptoms suggest iron deficiency: fatigue, pallor, or pica
- Annually for vegetarian or vegan children
- At the start of menstruation in adolescent girls
Treating Low Ferritin
Ferritin below 15 ng/mL warrants treatment regardless of hemoglobin level. Oral iron supplementation, dietary optimization, and identification of underlying causes are the pillars of management.
Contact NuLine to learn about pediatric iron studies.