Percentage of hypochromic red cells as a potential screening test to evaluate iron status in blood donors

Haemoglobin (Hb) levels are used to assess eligibility for blood donation but are not correlated with iron status. The percentage of hypochromic red cells (%Hypo-He) has been suggested as a useful screening parameter for iron deficiency. The aim of this study was to determine the cut-off level and accuracy of %Hypo-He screening among blood donors.

A total of 170 blood donors were recruited into the study. Blood donors were classified into three groups: normal, latent iron deficiency and iron deficiency anaemia based on their Hb, serum ferritin and transferrin saturation (TSAT) levels. The diagnostic performance of %Hypo-He was evaluated with a validation group comprising 160 blood donors.

Receiver operating characteristic (ROC) curve analysis showed that %Hypo-He is an excellent parameter for detecting iron deficiency, with an area under the curve (AUC) of 0.906, a confidence interval (CI) of 0.854-0.957 at a cut-off of 0.6%, and 74.51% sensitivity and 88.24% specificity. A moderate negative correlation between %Hypo-He and TSAT (ρ = -0.576 [P < 0.001]) and a strong negative correlation between %Hypo-He and serum ferritin (ρ = -0.703 [P < 0.001]) were found. A cut-off value of 0.6% was applied to the validation group and showed 82.9% sensitivity and 96% specificity.

%Hypo-He with a cut-off value of 0.6% is a potential parameter with high sensitivity and specificity for evaluating iron status among blood donors. This parameter is suitable for screening because its measurement has a faster turnaround time than biochemical markers.