Haematological and CD4+ T cells reference ranges in healthy adult populations in Gojjam zones in Amhara region, Ethiopia

Establishing national population haematological and immunological reference ranges are essential for clinical management of patients. However, there is scarcity of information on community based haematological reference ranges established from Ethiopian population. Therefore, this study aimed at determining haematological and CD4+ T cells reference ranges in healthy adults from East and West Gojjam zones, Ethiopia. Community based cross-sectional study was conducted from May 2015 to December 2015 in healthy adult residents of Gojjam zone. A total of 481(246 females and 235 males) healthy adults enrolled in the study. Healthy adults were defined by medical history, physical examination and laboratory screening for HIV, HBV, HCV and intestinal parasitosis. Haematological parameters were measured using haematology analyzer MindrayBC320 (Mindray Biomedical electronic Corporation, China). CD4+Tcells were enumerated using FACS count (Becton Dickinson). The median age of the participants was 25 years. The overall median and 95th percentile of CD4+ T cells count were 869 cells/mm3 and396-1598 cells/mm3, respectively. Females had a significantly higher CD4+ T cell counts compared to males (P = 0.002). The 95th percentile range for red blood cells (RBCs) was 3.93-6.1 x 106cells/mm3and for hematocrit (Hct) was 40-58% while for hemoglobin (Hb) was 15.69-17.84g/dl. Males had significantly higher values of RBC and Hct than females (P < 0.001). Females (120-379 x 106 cells/mm3) had significantly higher platelet counts than males (106-352 x106 cells/mm3) (P < 0.001). The overall median of WBC was6.78 x103/mm3and its95thpercentile range was3.5-11.5 x103/mm3. The overall 95th percentile range of MCV, MCH and MCHC were 89.5-107.5 fl, 28-34 pg and 30-33.2g/dl, respectively. The higher mean absolute count of RBCs was found in the youngest age groups (P = 0.03). The mean count of RBCs and Hct were significantly higher in highschool completed and above than other participants (P < 0.001). The lower and upper limit of platelet counts was significantly higher in highland (118 -383x106 cells/mm3) compared to lowland residents (107-352 x106 cells/mm3) (P < 0.001). Moreover, it was significantly higher in residents with better monthly income (124-383 x106 cells/mm3) compared to the counters (115-368 x106 cells/mm3) (P = 0.02). Some of the haematological and CD4+ T cells reference ranges of the healthy adults in this study showed variations with the reference ranges used and reported