Reference Ranges for the Clinical Laboratory Derived from a Rural Population in Kericho, Kenya

Abstract

The conduct of Phase I/II HIV vaccine trials internationally necessitates the development of region-specific clinical reference ranges for trial enrolment and participant monitoring. A population based cohort of adults in Kericho, Kenya, a potential vaccine trial site, allowed development of clinical laboratory reference ranges. Lymphocyte immunophenotyping was performed on 1293 HIV seronegative study participants. Hematology and clinical chemistry were performed on up to 1541 cohort enrollees. The ratio of males to females was 1.9∶1. Means, medians and 95% reference ranges were calculated and compared with those from other nations. The median CD4+ T cell count for the group was 810 cells/µl. There were significant gender differences for both red and white blood cell parameters. Kenyan subjects had lower median hemoglobin concentrations (9.5 g/dL; range 6.7–11.1) and neutrophil counts (1850 cells/µl; range 914–4715) compared to North Americans. Kenyan clinical chemistry reference ranges were comparable to those from the USA, with the exception of the upper limits for bilirubin and blood urea nitrogen, which were 2.3-fold higher and 1.5-fold lower, respectively. This study is the first to assess clinical reference ranges for a highland community in Kenya and highlights the need to define clinical laboratory ranges from the national community not only for clinical research but also care and treatment.

Reference Values for Some Renal Function Parameters for Adult Population in North-Rift Valley, Kenya

“…Similar findings were noted in Rwanda [8]. Sex differences in UA have been previously documented by Roche Diagnostics, Eller et al, Saathoff et al and Khan et al [2,4,5,9] which could be due to the influence of sex hormones resulting in differences in body mass between sexes. The general absence of sex differences for BUN, CA, and PHOS in this study agrees with those reported in the reagent manufacturer's reference range values [2]; the result is similar to studies done in Pakistan [10], an indication that these parameters are not influenced by sex hormones.…”

“…Male creatinine values for the current study were lower than those for America, Kericho and Kuwait groups [2,5,11], greater than those for Tanzanian population [3] and comparable with those of the Uganda group [4]. North Rift female creatinine values were higher than the America, Mbeya, and Kampala [2][3][4] but lower than those for Kericho populations [5].…”

“…The North Rift Kenya values for urea were lower than those of America and Kuwait [2,11], comparable with the Kampala, Uganda group [4] but slightly higher than those for Mbeya, Tanzania and Kericho, Kenya [3,5]. Male creatinine values for the current study were lower than those for America, Kericho and Kuwait groups [2,5,11], greater than those for Tanzanian population [3] and comparable with those of the Uganda group [4].…”

“…Laboratory reference values for populations from western countries are widely published in scientific literature [2], textbooks and on the worldwide web. However, there is a general lack of published data regarding laboratory parameters for populations living in tropical sub-Saharan Africa [3] and the few studies that have been undertaken have indicated differences in reference values of African populations compared to those derived from western populations [3][4][5][6]. These differences suggest the need for the development of locally derived reference values.…”

“…These differences suggest the need for the development of locally derived reference values. Reference values are used to aid in interpreting results of laboratory measurements, clinical trials screening and as the basis of safety monitoring for trial participants [3,5,6]. These reference values are used to assess health in humans and are based on the effective performance of the major body organs such as the liver, pancreas, heart and kidney.…”