Hematologic and immunologic parameters in Zimbabwean infants: a case for using local reference intervals to monitor toxicities in clinical trials.

Studies investigating novel therapies in African infants report laboratory adverse events based on reference intervals from white Western infants. However, prior studies have shown that reference intervals differ based on ethnicity and geographic location. We calculated reference intervals for Zimbabwean infants by analyzing the hematologic and immunologic values found in 542 blood samples from 269 HIV-uninfected, black, Zimbabwean infants at 3, 5 and 9 months of age. Substantial proportions of the platelet counts (44%), hemoglobins (19%) and mean corpuscular volumes (41%) were outside published normal ranges. The majority (65%) of hemoglobin values qualified as a United States National Institutes of Health Division of AIDS adverse events. The majority (71%) of CD4% values indicated immunodeficiency by World Health Organization criteria. Hematologic and immunologic reference intervals used to evaluate toxicities in pediatric trials in sub-Saharan Africa need to be reevaluated to account for differences in ethnicity, geographic location, nutrition and socioeconomic status.