Haemoglobin and red blood cell reference intervals during infancy

Abstract

ObjectivesThere is a need for updated haematological reference data in infancy. This study aimed to define intervals for haemoglobin and red blood cell biomarkers based on data from a large cohort of longitudinally followed Swedish infants.DesignLongitudinal cohort study.SettingTwo Swedish study centres.ParticipantsThree community-based populations including 442 presumably healthy infants born at term and with umbilical cord clamping delayed to 30 s or more after birth.MethodsBlood samples were collected from umbilical cord blood (a), at 48–118 hours (b), at 4 months (c) and at 12 months (d). Reference intervals as the 2.5th and 97.5th percentiles were calculated in coherence with Clinical and Laboratory Standards Institute guidelines.ResultsReference intervals for haemoglobin (g/L) were: (a) 116–189, (b) 147–218, (c) 99–130, (d) 104–134, and for mean cell volume (fL): (a) 97–118, (b) 91–107, (c) 71–85, (d) 70–83. Reference intervals for erythrocyte counts, reticulocyte counts, reticulocyte haemoglobin, mean cell haemoglobin and mean cell haemoglobin concentration were also estimated. According to the WHO definition of anaemia, a haemoglobin value less than 110 g/L, 16% of this presumably healthy cohort could be classified as anaemic at 12 months.ConclusionWe found mainly narrower reference intervals compared with previously published studies. The reference intervals for each parameter varied according to the infants’ age, demonstrating the necessity of age definitions when presenting infant reference intervals. The discrepancy with the WHO classification for anaemia at 12 months, despite favourable conditions in infancy, needs future investigation.

Lower iron stores were associated with suboptimal gross motor scores in infants at 3–7 months

“…In a recently published reference material for ret-Hb, the 2.5th percentile was used as the lower limit, equivalent to a ret-Hb of 25 pg with 90% confidence interval of 21-25 pg. 22 In the present study, we combined biochemical data with AIMS, a validated assessment of gross motor development, commonly used in research and clinical settings. Even with our small sample size, we clearly demonstrated that a ret-Hb <28 pg was associated with suboptimal gross motor scores.…”

“…Different cut‐offs for ret‐Hb have been proposed but have relied on biochemical data only. In a recently published reference material for ret‐Hb, the 2.5th percentile was used as the lower limit, equivalent to a ret‐Hb of 25 pg with 90% confidence interval of 21–25 pg 22 . In the present study, we combined biochemical data with AIMS, a validated assessment of gross motor development, commonly used in research and clinical settings.…”

“…Ret-Hb correlated with AIMS z-score (r = 0.320, 95% CI 0.074-0.529, n = 61, p = 0.012). Infants scoring <10th percentile on AIMS had lower ret-Hb (median [IQR] = 26[22][23][24][25][26][27]) compared with infants scoring ≥10th percentile on AIMS (median [IQR] = 30[29- 32], p < 0.001, Mann-Whitney U, n = 61). The 6/14 (43%) of infants with ret-Hb <28 pg scored <10th percentile on AIMS compared to 1/47 (2.1%) of infants with ret-Hb ≥28 μg/L (Exact, p < 0.001).…”

Hemoglobin and Its Z Score Reference Intervals in Febrile Children: A Cohort Study of 98,572 Febrile Children

“…Childhood anemia is a widespread health concern impacting young children [ 1 , 2 ] and the hemoglobin (Hb) reference varies according to the children’s age, especially in the infant period [ 3 ]. Several studies have established detailed age- and sex-specific reference intervals for hematologic parameters in healthy children [ 4 , 5 ].…”

“…The World Health Organization (WHO) classifies anemia in children under 5 years of age as a condition where the Hb concentration is below 11 g/dL without arbitrary references [ 3 ]. Anemia or decreased Hb levels can be observed in febrile children and may indicate various underlying causes, including infectious or inflammatory conditions [ 23 , 24 ].…”