What are normal hemoglobin (Hb) and hematocrit (Hct) levels for a 12-month-old child?

Normal Hemoglobin and Hematocrit for a 12-Month-Old Child

For a healthy 12-month-old child, normal hemoglobin is approximately 11.0-14.0 g/dL, with an average around 12.0-12.5 g/dL, and normal hematocrit is approximately 33-42%. 1

Age-Specific Reference Values

• Hemoglobin below 11.0 g/dL at 12 months of age is considered anemia and warrants evaluation for iron deficiency 2, 1, 3
• The average serum hemoglobin concentration for children aged 6-24 months ranges from 12.0-12.5 g/dL 1
• Hematocrit below 33% at 12 months is considered low and should prompt further investigation 4

Physiologic Context

• Hemoglobin values undergo significant changes during infancy: they are highest at birth (approximately 17 g/dL), decrease to a physiologic nadir around 2-3 months of age (9-11 g/dL), then gradually increase throughout childhood 5
• By 12 months, hemoglobin levels have recovered from the physiologic nadir and stabilize in the 11-14 g/dL range 1, 3

Clinical Screening Thresholds

• The CDC recommends universal anemia screening at 9-12 months of age for high-risk populations (low-income families, WIC-eligible children, migrant children, recently arrived refugees) 2
• For children not at high risk, selective screening should be performed only if risk factors are present, including: 2
  • Preterm or low birthweight
  • Non-iron-fortified formula feeding for >2 months
  • Introduction of cow's milk before 12 months
  • Breastfed infants without adequate iron supplementation after 6 months
  • Consumption of >24 oz daily of cow's milk
  • Special health-care needs

Important Caveats

• Hemoglobin alone is insufficient for diagnosing iron deficiency, as less than 50% of children aged 1-5 years with anemia (Hb <11.0 g/dL) are actually iron deficient 2, 1
• Other causes of anemia at this age include infection (which can cause transient anemia), thalassemia, sickle cell disease, and other nutritional deficiencies 2
• Acute infections can significantly lower hemoglobin levels temporarily—91% of children aged 6-47 months with ESR ≥50 mm/hour had Hb <11.0 g/dL, and this anemia is typically reversible and unrelated to iron deficiency 6
• Altitude affects hemoglobin levels, with an increase of approximately 0.2 g/dL per 1,000 meters above sea level 1

Diagnostic Approach When Anemia is Detected

• If screening hemoglobin is <11.0 g/dL, repeat the test to confirm 2
• If confirmed and the child is not acutely ill, presume iron-deficiency anemia and initiate treatment with 3 mg/kg/day of elemental iron 2
• Recheck hemoglobin in 4 weeks: an increase of ≥1 g/dL confirms iron-deficiency anemia 2
• If no response after 4 weeks despite compliance, perform additional testing including MCV, RDW, and serum ferritin 2
• Red cell distribution width (RDW) >14% with low MCV suggests iron-deficiency anemia, while RDW ≤14% with low MCV suggests thalassemia 2, 4