Reference intervals for hemoglobin and mean corpuscular volume in an ethnically diverse community sample of Canadian children 2 to 36months

ObjectiveTo establish reference intervals for hemoglobin and mean corpuscular volume (MCV) in an ethnically diverse community sample of Canadian children 36months and younger.MethodsWe collected blood samples from young children at scheduled primary care health supervision visits at 2weeks, 2, 4, 6, 9, 12, 15, 18, 24, and 36months of age. Samples were analyzed on the Sysmex XN-9000 Hematology Analyzer. We followed the Clinical and Laboratory Standards Institute guidelines in our analysis. Data were partitioned by sex and also combined. We considered large age partitions (3 and 6months) as well as monthly partitions. Reference intervals (lower and upper limits) and 90% confidence intervals were calculated.ResultsData from 2106 children were included. The age range was 2weeks to 36months, 46% were female, 48% were European and 23% were of mixed ethnicity. For hemoglobin, from 2 to 36months of age, we found a wide reference interval and the 90% confidence intervals indicated little difference across age groups or according to sex. For MCV, from 2 to 7months of age there was considerable decrease in the reference interval, which was lowest during the second year of life, followed by a slight increase in the last months of the third year of life.ConclusionThese findings suggest adoption of a single hemoglobin reference interval for children 2-36months of age. Further studies in children under 4months of age are needed.Trial registrationTARGet Kids! cohort is registered at ClinicalTrials.gov. www.clinicaltrials.gov. Identifier: NCT01869530.

Automated summary

This study aimed to establish reference intervals for hemoglobin and mean corpuscular volume (MCV) in a diverse community sample of Canadian children 36 months and younger. Results showed a wide reference interval for hemoglobin across different age groups, as well as notable variations in mean corpuscular volume throughout the age range.