Higher Ferritin Threshold May Improve Iron Deficiency Detection in Children

Iron deficiency in school-age children can affect brain development, learning, growth, and physical performance, yet early deficiency may be missed when screening focuses mainly on anemia. Ferritin, a protein that stores iron in cells and releases it when needed, helps supply the iron used to make hemoglobin, the oxygen-carrying protein in red blood cells. Because iron deficiency can occur before hemoglobin falls to anemic levels, relying mainly on low hemoglobin may miss earlier, treatable stages. A new study suggests that using a higher ferritin threshold could identify iron deficiency sooner in many U.S. children aged 5 to 14 years.

Researchers at the Centers for Disease Control and Prevention (CDC) developed a method to establish a ferritin cutoff for U.S. school-age children by analyzing changes in red blood cells (RBCs) and how the body produces them. The findings indicate that iron levels may already be insufficient for normal RBC production when ferritin is less than 24 μg/L, a threshold higher than current recommendations.

The study analyzed data from 3,765 otherwise healthy children aged 5 to 14 years (mean 10.3 years) who participated in NHANES III (1988–1994), excluding those with signs of infection, inflammation, or liver-related issues, or with missing ferritin, hemoglobin, or zinc protoporphyrin (ZPP) data. Using the updated method, about 30% of children in the sample were classified as iron deficient, compared with 9% identified using previous approaches. Current CDC and World Health Organization guidelines identify iron deficiency at a ferritin threshold around 15 μg/L.

Results were consistent across ages and sexes, with overall iron needs similar for boys and girls in this growing life stage. Iron deficiency was higher among older girls (12–14 years), likely due to menstrual blood loss. Supplemental analyses using more recent NHANES data (2017–2023) that included soluble transferrin receptor instead of ZPP found a consistent ferritin threshold, further validating the results. The study is published in Blood Red Cells & Iron, a journal of the American Society of Hematology. 

“Identifying the ferritin level in blood needed to support a child’s physical growth and learning is important because low iron levels can lead to serious health issues such as difficulties with concentration and learning, fatigue, and reduced physical performance,” said Yaw Addo, PhD, lead author and epidemiologist in the Division of Nutrition, Physical Activity, and Obesity at the Centers for Disease Control and Prevention (CDC).

“This study applied a new methodology to identify iron deficiency and found that iron can already be low and possibly start to affect children's health when ferritin is less than 24 μg/L. The findings of this study might help identify earlier stages of iron deficiency than the previously recommended cutoff. CDC is continuing to examine how these thresholds can be used by healthcare providers to improve detection of iron deficiency in children 5 to 14 years,” said Maria Elena Jefferds, PhD, coauthor and team lead in CDC’s Division of Nutrition, Physical Activity, and Obesity.

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American Society of Hematology