Age-Specific Hemoglobin Thresholds Defining Anemia in Children

The CDC defines anemia in children ≤15 years as hemoglobin <11.0 g/dL, which serves as the primary screening threshold for clinical practice. 1

Standard Hemoglobin Cutoffs by Age Group

Children ≤15 years of age: Hb <11.0 g/dL defines anemia 1
Children aged 1-2 years: The 5th percentile hemoglobin is approximately 11.0 g/dL, with mean values around 12.0-12.5 g/dL 2, 3
Infants 0-12 months: Iron stores from birth typically sustain normal hemoglobin until 4-6 months of age, after which dietary iron becomes critical 1

Children 6-11 years: Mean hemoglobin values range from 123.7-131.8 g/dL (12.4-13.2 g/dL) depending on specific age and sex 1
Children 12-14 years: Mean hemoglobin increases to 125.4-133.2 g/dL (12.5-13.3 g/dL), with emerging sex differences 1
Adolescents 15-19 years: Mean hemoglobin is 123.2-129.9 g/dL (12.3-13.0 g/dL), with continued sex-based variation 1

Hemoglobin thresholds must be adjusted upward for children living at higher elevations 1:

African-American children consistently show hemoglobin concentrations 0.5-0.9 g/dL lower than other racial groups at the same age and sex 1
Non-Hispanic Black children aged 1-2 years: Mean hemoglobin is 118.3 g/dL (11.8 g/dL) compared to 120.7 g/dL (12.1 g/dL) in other groups 1

Universal screening at 9-12 months is recommended for high-risk populations (low-income families, WIC-eligible children, migrants, refugees) 2
Selective screening should occur in non-high-risk children with specific risk factors: preterm birth, low birthweight, non-iron-fortified formula use >2 months, cow's milk introduction before 12 months 2
Additional screening between 15-18 months may be more effective at detecting nutritional anemia after weaning from iron-fortified formula 4

Repeat testing to confirm the low hemoglobin 2
Presume iron-deficiency anemia and initiate treatment with 3 mg/kg/day elemental iron 2, 3
Recheck hemoglobin in 4 weeks: An increase ≥1 g/dL confirms iron-deficiency anemia 2, 3
Evaluate RDW and MCV: RDW >14% with low MCV suggests iron deficiency; RDW ≤14% with low MCV suggests thalassemia 2, 3

Less than 50% of children aged 1-5 years with Hb <11.0 g/dL actually have iron deficiency 2, 3
Hemoglobin concentration cannot determine the cause of anemia; additional tests (serum ferritin, transferrin saturation, MCV, RDW) are essential 2
Other causes include infection, thalassemia, sickle cell disease, and other nutritional deficiencies 2, 5

Hemoglobin ≤4.8 g/dL requires immediate hospitalization and red blood cell transfusion due to high risk of cardiovascular decompensation 5
Hemoglobin <7.0 g/dL in hemodynamically stable hospitalized children warrants restrictive transfusion threshold consideration 3, 5

Iron-deficiency anemia defined as Hb ≤10.0-10.5 g/dL results in developmental delays, decreased motor activity, reduced social interaction, and attention deficits that may persist beyond school age 1
Even mild iron-deficiency anemia (Hb >10.0 but <11.0 g/dL) may affect neurocognitive development, though further study is needed 1

Children with chronic kidney disease: Target hemoglobin range of 11.0-12.0 g/dL during ESA therapy, with upper limit not exceeding 13.0 g/dL 1
Pregnant adolescents: Hemoglobin thresholds vary by trimester, with first trimester cutoff at 11.0 g/dL 1