Blood donation projections using hierarchical time series forecasting: The case of Zimbabwe’s national blood bank

Abstract

Abstract Background Accurate blood donation forecasting gives blood managers empirical evidence in blood inventory planning. The aim of the study is to model and predict blood donations using hierarchical time series forecasting techniques. The modelling technique allows one to identify, say, a declining donor category, and in that way, the method offers feasible solutions for blood managers to work on. Methods The monthly blood donations data covering the period 2007 to 2018, collected from the National Blood Service Zimbabwe (NBSZ), was used, resulting in a total of 144 monthly observations. The data was first disaggregated by gender (Male and Female), with further disaggregation by blood groups (A, B, AB and O) within each gender category. The R-package HTS was used to generate forecasts using the bottom-up, top-down and optimal combination methods. The Error-Trend-Seasonality (ETS) and Autoregressive Integrated Moving Average (ARIMA) methods were used to generate the forecasts. Results Blood group O had the highest monthly mean of 1507.85 and 1230.03 blood units for male and female donors, respectively. Male donors had higher mean blood donation projections compared to the female donors. The top-down forecasting proportions (TDFP) under ARIMA, with a MAPE value of 11.30, was selected as the best approach and used to forecast future blood donations. The future blood donation projections show a slight decline, which necessitates proactive measures by blood authorities to avert blood shortages. Conclusions Blood donation forecasting helps blood bank authorities in making decisions pertaining to blood donor recruitment, blood donation drives and resource allocations. The hierarchical forecasting approach is an alternative method that can be used in blood supply projections. The blood donation predictions showed seasonal trends with a slight decrease in total blood donations. Therefore, blood authorities in Zimbabwe could develop blood inventory interventions to ensure a sustainable blood supply in the near future.