Physiologically based ferritin thresholds for defining iron deficiency in U.S. Children 5-14 years

Background and objective: Iron deficiency (ID) is the most predominant nutritional deficiency globally. The current CDC iron guideline for ID screening uses serum ferritin (Ft) ≤15 μg/L for all individuals 6 months and older and was based on bone-marrow assessment. We aimed to evaluate physiologically based Ft thresholds for defining ID in children aged 5-14 years.

Methods

Ferritin and hemoglobin (Hb) data were analyzed from 3765 apparently healthy (no inflammation, infection, or risk of iron overload) US children, since such data are an indicator of iron-deficient erythropoiesis, erythrocyte zinc protoporphyrin (eZnPP). Nonlinear ferritin concentration curves (Hb-Ft, eZnPP-Ft) and differential equations were applied to identify ferritin thresholds at ID onset with inflection minima and plateau for each iron analyte.