keywords haematology, reference intervals, normal values, infants, children, Africa ..... trial assessing the safety and immunogenicity of AS01 and AS02.
Tropical Medicine and International Health
doi:10.1111/j.1365-3156.2010.02705.x
volume 16 no 3 pp 343–348 march 2011
Haematological and biochemical reference intervals for infants and children in Gabon Alexander Humberg1,2, Judith Kammer1,2, Benjamin Mordmu¨ller1,2, Peter G. Kremsner1,2 and Bertrand Lell1,2 1 Medical Research Unit, Albert Schweitzer Hospital, Lambare´ne´, Gabon 2 Institute of Tropical Medicine, University of Tu¨bingen, Tu¨bingen, Germany
Summary
objectives To establish reference intervals for major haematological and biochemical parameters in Gabonese infants and children. methods The reference sample population consisted of 226 healthy infants (4–9 weeks of age) and 185 healthy children (18–60 months of age). Basic red cell parameters as well as total and differential white blood cell counts were performed. Clinical chemistry parameters consisted of glutamate–pyruvic transaminase and creatinine, and total bilirubin was measured in children. Statistical analysis was based on the guidelines of the Clinical and Laboratory Standards Institute. Nonparametric methods were used to determine 95% reference limits and their 90% confidence intervals. results Compared to European populations, values for several red cell parameters (haemoglobin, haematocrit, red blood cell count, mean corpuscular volume) were lower and platelet counts were higher. Eosinophils were higher in the older age group, most likely caused by intestinal helminths. conclusions The study confirms the importance of establishing reference limits for local populations. The reference ranges could be used as a benchmark for similar populations in Central Africa. keywords haematology, reference intervals, normal values, infants, children, Africa
Introduction Laboratory reference values are essential for clinical practice and have therefore been established for numerous populations. However, in African regions, there is a dearth of published reference limits, and these are therefore often taken from textbooks, whose values are based on those of Western populations. Previous studies have questioned this practice (Lugada et al. 2004; Quinto´ et al. 2006) because of the differences in nutritional, environmental and genetic factors among these populations. To improve quality in health care and clinical research, it is therefore essential to establish and publish reference values for local African populations. We determined reference values for the major parameters of complete and differential blood count and for basic clinical chemistry parameters in infants and children from the Moyen-Ogooue´ province in Gabon.
Materials and methods Geography and epidemiology Gabon has a tropical climate with an extensive system of rainforests. Endemic malaria transmission, with an esti-
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mated incidence of around 0.2–1.5 Plasmodium falciparum episodes per person per year (Lell et al. 1999; WHO 2005; May et al. 2008) is an important cause of morbidity. There is little seasonal variability in transmission rates or parasite prevalence (Wildling et al. 1995; Sylla et al. 2000). Plasmodium falciparum is the predominant species and responsible for 95% of all malarial infections. Depending on area of residence, the prevalence of schistosomiasis infection varies and increases with age (Van den Biggelaar et al. 2001). Intestinal helminths are highly prevalent among children living in Lambare´ne´. In 1998, 46% of the children were estimated to be infected with Ascaris lumbricoides and 71% with Trichuris trichiura (Van den Biggelaar et al. 2001). Subjects The haematological and biochemical values are based on data derived from healthy Gabonese children who were seen during the screening visits of two trials with an anti-malaria vaccine candidate in the Medical Research Unit of the Albert Schweitzer Hospital in Lambare´ne´, Gabon (Lell et al. 2009). In spring 2006, blood was taken from healthy children aged 18 months to 5 years (60 months). Infants aged 4–9 weeks were seen between May 2007 and January 2008. 343
Tropical Medicine and International Health
volume 16 no 3 pp 343–348 march 2011
A. Humberg et al. Haematological and biochemical reference intervals
A thorough history and medical examination was performed at screening, and the participants were followed closely over several months. Both trials were monitored by external study monitors to ensure accuracy and consistency of the data. All blood samples were taken in the morning. Venipuncture in children aged 4–9 weeks was performed on the back of the hand using a sterile cannula. Children aged 18 months to 5 years were venipunctured in an antecubital vein. Participants with any of the following criteria were excluded from the reference sample group: acute or serious chronic disease, recent use of investigational or nonregistered drugs, administration of immunoglobulins, blood transfusions within 3 months preceding the blood sampling, administration of immunosuppressants within 6 months prior to blood sampling, same sex twin, a family history of congenital or hereditary immunodeficiency, history of splenectomy, major congenital defects, weightfor-age z-score
