RESUMEN
Reliable laboratory diagnostic results are key for evaluating and improving children's health. To interpret these results, child-specific reference intervals (RIs), which account for constant biological changes and physiological development with sex and age, are required, as recommended by the Clinical and Laboratory Standards Institute (CLSI). This study presents age- and sex-specific reference intervals for complete blood count (CBC) parameters in children (<1-12 years old) in the Northern Region of Ghana. In this cross-sectional study, 600 healthy children from randomly sampled schools in Tamale (the Northern Region) were recruited and screened. Data from 388 eligible children were used to nonparametrically determine the reference intervals of CBC parameters at the 2.5th and 97.5th percentiles. The CBC reference intervals were compared for variations in sex and age groups using the Wilcoxon rank-sum test. There were no statistically significant differences in most CBC parameters by sex (RBC, Hb, HCT, MCH, RDW (CV/SD), WBC, LYM#, MON#(%) NEU#(%), EOS#(%), and BAS#(%); p > 0.05) and age group (RBC, MCV, RDW (CV/SD), WBC, LYM#, MON#(%) NEU#(%), EOS#(%), and BAS%; p > 0.05). However, there were observable differences between this locally established CBC reference interval and that used for children at Tamale Teaching Hospital (manufacturer's RIs). This study emphasises the importance of determining reference intervals representative of the local child population and incorporating them into the current reporting system of laboratories in the Northern Region to ensure the provision of effective and efficient healthcare services.