Haematological reference ranges for schoolchildren

Abstract

There are few reports of reference ranges for haematological values in school age children and most studies extend over a small age range or have excluded a considerable proportion of the study population in an effort to omit those with haemoglobinopathies or anaemia. Blood samples from 2135 children aged 4-19 years, from randomly selected schools, were analysed by automated counter. Reference ranges for red cell, white cell and platelet indices are provided from the results. Median haemoglobin and red blood cell count values for girls and boys rose together with increasing age, up to 12 years, but then diverged. Girls had a higher platelet count than boys. Mean platelet volume rose with age and was inversely related to the platelet count. Plateletcrit fell with age but in girls there was a peri-pubertal peak. Total leucocyte count fell with age. The upper limits for total leucocyte count in this study are approximately 2 x 10(9) lower than those quoted in modern haematology textbooks. Lymphocyte, eosinophil and basophil counts fell with age with little difference between the sexes. Neutrophil and monocyte counts were similar for younger girls and boys but diverged in the older children with the older girls having higher values than boys.

Complex Biological Profile of Hematologic Markers across Pediatric, Adult, and Geriatric Ages: Establishment of Robust Pediatric and Adult Reference Intervals on the Basis of the Canadian Health Measures Survey

“…Similar to other studies, we found that platelet count decreased with age during childhood (24 ) and that adult women had slightly higher counts than men, but levels tended to decrease with age in both sexes (2,25 ). Thrombopoietin, a hormone that regulates production of platelets, has been found to peak shortly after birth and gradually decline to adult concentrations (26 ), which could explain the higher platelet counts observed in early childhood.…”

Normal Reference Values for Hematological Parameters, Red Cell Indices, Hb A2 and Hb F from Early Childhood Through Adolescence in Saudis

“…5,12,19,24,26 Environmental factors and altitude also influence the value of hematological parameters. 10 Saudi Arabia forms the largest part of the Arabian Peninsula and occupies over 2.2 million square kilometers. 33 It is probably among the driest countries in the world, with long, hot and almost totally dry summers, and a short very cool winter season during which rain occurs.…”

“…Extensive studies during the last three to four decades conducted in different populations have worked out normal reference ranges for hematological parameters in adults and children, [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] and have reported significant differences in different ethnic groups. 3,5,12,14,18,24,26 In African-American, African and Afro-Caribbean children, the levels of these parameters are generally lower than in Caucasians.…”

“…[9][10] Several studies have been carried out in children at various ages and in adolescents, and significant differences have been reported in different populations, seasons, racial and ethnic groups and gender subgroups. [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] Genetic factors are shown to significantly contribute to all blood cell measures, accounting for between 61%-96% of variance. 11,25 In almost all studies, the ethnic and sex differences are significant, with Caucasian values being higher than those of Africans and Afro-Caribbeans.…”

Provisional Kuwaiti Children Hematology Reference Range

“…Moreover, appropriate diagnosis and treatment can reduce the infant and children morbidity and mortality rates [10]. In several studies significant differences in hematology reference range have been found in children at various ages and adolescents in different populations, seasons, racial ethnic groups, and gender subgroups [11,12].…”