Normal Ferritin Level for a Grade School Girl
For a healthy grade school girl (approximately ages 6-12), the normal serum ferritin level is approximately 30 μg/L, based on CDC reference values for children aged 6-24 months, which serves as the pediatric baseline. 1
Age-Specific Reference Values
- The CDC establishes that the average serum ferritin value for children aged 6-24 months is approximately 30 μg/L. 1
- While specific data for grade school age (6-12 years) is limited in the provided evidence, pediatric ferritin values typically remain in this range through childhood until adolescence, when sex-specific differences emerge.
Clinical Interpretation Thresholds
Iron Deficiency Indicators:
- Ferritin <15 μg/L has 99% specificity for absolute iron deficiency in children, making it the gold standard diagnostic threshold. 1
- Ferritin levels <30 μg/L generally indicate low body iron stores and warrant clinical attention. 1
- Recent physiologically-based evidence suggests that ferritin thresholds of 22.1 μg/L (95% CI 20.8-23.4) correspond to the starting point of decline in hemoglobin concentrations in children aged 6-59 months. 2
Important Clinical Context:
- The WHO guideline threshold of <12 μg/L for children under 5 years significantly underestimates iron deficiency prevalence compared to physiologically-based thresholds. 2
- Using physiologically-based thresholds (approximately 22 μg/L), the prevalence of iron deficiency in children is 34.2% compared to only 16.6% using current WHO guidelines (p<0.0001). 2
Critical Caveats for Interpretation
Inflammation Confounds Ferritin:
- Ferritin is an acute-phase protein that rises during infections, inflammation, or tissue damage, potentially masking true iron deficiency. 1
- In the presence of inflammation (elevated CRP/ESR), iron deficiency may be present even with ferritin levels up to 50-100 μg/L. 1
- When inflammation is suspected, check inflammatory markers (CRP, ESR) and consider transferrin saturation (TSAT <20% indicates iron deficiency even with higher ferritin). 1
Practical Clinical Algorithm
For a grade school girl with measured ferritin:
- Ferritin <15 μg/L: Absolute iron deficiency confirmed—initiate iron supplementation and investigate source of deficiency. 1
- Ferritin 15-30 μg/L: Low iron stores likely—consider dietary iron optimization and oral supplementation. 1
- Ferritin 30-50 μg/L: Borderline—assess for symptoms (fatigue, reduced exercise tolerance) and consider supplementation if symptomatic. 1
- Ferritin >50 μg/L: Generally adequate iron stores in the absence of inflammation. 3, 1
Key Takeaway for Practice
The "normal" ferritin of approximately 30 μg/L represents an average, but optimal iron stores for preventing functional consequences may require ferritin levels closer to 50 μg/L. 4 This is particularly important for active children, as iron deficiency without anemia can still cause fatigue and reduced exercise tolerance. 1