Normal Serum Ferritin Range for a 9-Year-Old Child
For a healthy 9-year-old child, the normal serum ferritin reference range is approximately 4-55 μg/L, with a mean value around 24-30 μg/L. 1, 2, 3
Age-Specific Reference Values
The CDC establishes that average serum ferritin for children is approximately 30 μg/L, which serves as the baseline reference point for pediatric populations 1, 2
A study specifically examining 9-12 month old infants found reference values (5th-95th percentiles) of 4-55 μg/L with a mean of 24 μg/L 3, and these values remain relatively stable through childhood until adolescence when sex-specific differences emerge 2
A population-based study of 6-12 year old children (which directly includes 9-year-olds) established reference intervals using the 2.5th-97.5th percentiles, finding no need for age or sex partitioning within this age group 4
Clinical Interpretation Thresholds
Ferritin <15 μg/L has 99% specificity for absolute iron deficiency in children and definitively confirms iron deficiency requiring supplementation 1, 2
Ferritin values <10.9 μg/L provide optimal diagnostic accuracy (83% sensitivity, 80% specificity) for iron deficiency in children aged 9-12 months 3
Recent physiologically-based evidence suggests ferritin thresholds around 20 μg/L may be more appropriate for identifying iron-deficient erythropoiesis in children, as this represents the point where hemoglobin begins to decline and soluble transferrin receptor begins to rise 5
Ferritin levels <30 μg/L generally indicate low body iron stores and warrant clinical attention, even if not meeting strict deficiency criteria 2
Critical Caveats for Interpretation
Ferritin is an acute-phase reactant that rises during inflammation, infection, or tissue damage, potentially masking true iron deficiency 6, 2
In the presence of inflammation, iron deficiency may exist even with ferritin levels up to 50-100 μg/L 1, 2
When inflammation is suspected, check C-reactive protein and consider transferrin saturation (<16-20%) as a more reliable indicator of functional iron deficiency 1
Serum ferritin combined with transferrin saturation provides the most comprehensive assessment of both stored iron (ferritin) and circulating iron available for erythropoiesis (transferrin saturation) 6
Practical Clinical Algorithm for a 9-Year-Old
Ferritin <15 μg/L: Absolute iron deficiency confirmed; initiate iron supplementation and investigate underlying cause 1, 2
Ferritin 15-30 μg/L: Low iron stores likely; optimize dietary iron intake and consider oral supplementation 2
Ferritin >30 μg/L but <50 μg/L: Generally adequate stores in absence of inflammation; monitor if risk factors present 2
Ferritin >50 μg/L: Iron stores adequate unless inflammation present (check CRP/ESR if clinical suspicion) 2
Additional Considerations
Soluble transferrin receptor (sTfR) concentrations are physiologically higher in children than adults, with mean values around 7.0 mg/L in prepubertal children compared to 5.8 mg/L in adults 7
The sTfR/log ferritin index has a reference range of 0.49-1.46 in healthy children aged 1-11 years 8, and remains useful for detecting iron deficiency even when ferritin is elevated due to inflammation 6
Reticulocyte hemoglobin content provides insight into iron availability over the past few days and has been included in American Academy of Pediatrics guidelines as an early marker for iron-restricted erythropoiesis 6