Evaluation of the Performance of Copper Sulphate and Hemocue Methods for Haemoglobin Estimation Among Blood Donors in Dar Es Salaam, Tanzania

Abstract

Background: The National Blood Transfusion Service (NBTS) in Tanzania uses the Copper Sulphate (CuSO4) gravimetric method to estimate hemoglobin (Hb) in blood donors. However, this and other point-of-care methods, including HemoCue, may provide false results. Therefore, this study aimed to evaluate the performance of CuSO4 and HemoCue methods for Hb estimation compared with automated haematology analyzer (AHA).
Methods: The cross-sectional study was conducted among (N=204) blood donors in Dar es Salaam. Capillary blood samples were obtained for Hb estimation by CuSO4 and HemoCue methods, 3 mls of venous blood were also collected for Hb quantification by AHA (gold standard), HemoCue and CuSO4 gravimetric method. Data were analyzed by Epi info 7.2.2.6, statistical significance was defined at a P value of <0.05, and kappa agreement was calculated.
Results: The median age of the study participants was 30 years (IQR: 20-39). The proportion of false eligible donors was 19.6%, and false deferral donors were 2.9% by the CuSO4 gravimetric method. The specificity, sensitivity, positive and negative predictive values, and Kappa agreement for CuSO4 were 28.6%, 95.9%, 78.0%, 72.7%, and 0.1, respectively. In contrast, the specificity, sensitivity, positive and negative predictive values, and Kappa agreement for HemoCue were 62.5%, 98.6%, 87.4%, 94.6%, and 0.63, respectively.
Conclusion: Our study revealed that the performance of the CuSO4 gravimetric method in Tanzania is relatively poor, with a high proportion of false eligible donors than the HemoCue method. These findings warrant further studies to evaluate the quality control measures for CuSO4 gravimetric method and explore alternative point-of-care methods for Hb estimation among blood donors in similar resource limited-settings.