Haemoglobin and red blood cell reference intervals during infancy

Area of Science:

• Pediatrics
• Hematology
• Clinical Chemistry

Background:

• Establishing accurate hematological reference data for infants is essential for diagnosing and managing various conditions.
• Previous reference intervals may not reflect current infant populations or practices, such as delayed cord clamping.

Purpose of the Study:

• To define updated reference intervals for hemoglobin and red blood cell biomarkers in a large cohort of longitudinally followed Swedish infants.
• To provide age-specific reference data crucial for accurate interpretation in pediatric hematology.

Main Methods:

• A longitudinal cohort study involving 442 healthy, term-born Swedish infants with delayed umbilical cord clamping.
• Blood samples were collected at multiple time points: umbilical cord, 48-118 hours, 4 months, and 12 months.
• Reference intervals were calculated as the 2.5th and 97.5th percentiles following Clinical and Laboratory Standards Institute guidelines.

Main Results:

• Narrower reference intervals for hemoglobin and mean cell volume were observed compared to previous studies.
• Significant age-dependent variations in reference intervals for all measured hematological parameters were identified.
• At 12 months, 16% of the cohort met the WHO definition of anemia (hemoglobin < 110 g/L), despite favorable birth conditions.

Conclusions:

• The study highlights the necessity of age-specific reference intervals for infant hematological parameters.
• The established narrower reference intervals provide a more precise benchmark for clinical assessment.
• The observed discrepancy with WHO anemia classification warrants further investigation into factors influencing infant hemoglobin levels.