Immunohaematological reference values for HIV-negative healthy adults in Botswana

BACKGROUND Clinical laboratories in Botswana have relied entirely on the reference intervals for normal immunohaematological values provided by manufacturers' kits and textbooks. OBJECTIVES The aim of this study was to determine the means, medians, 2.5th and 97.5th percentile reference intervals, for normal immunohaematological values in healthy adults in Botswana. METHOD A total of 261 healthy participants comprising 126 men (48%) and 135 (52%) women were enrolled in the southern part of Botswana, and immunological and haematological laboratory parameters were measured. RESULTS The mean age was 28.8 (95% Confidence Interval [CI] 27.7-29.8) years, with a median of 27 years and a range 18-66 years. The mean haemoglobin level was significantly lower for women (12.4 g/dL; 95% CI 12.1% - 12.7%) than men (15.1 g/dL; 95% CI 14.9% - 15.3%). The women's haemoglobin reference values (9.0 g/dL - 15.0 g/dL) levels were lower than observed in predominantly White populations (12.0 g/dL - 16.0 g/dL), but comparable with regional consensus reference intervals (9.5 g/dL - 15.8 g/dL) recently defined for East and Southern Africa. CONCLUSION The established values provide an important tool for patient management and could influence decisions on inclusion of participants and adverse events in clinical trials conducted locally.