Prognostic value of red blood cell parameters and ferritin in predicting deferral due to low hemoglobin in whole blood donors.

Risk factors for deferral from red blood cell (RBC) donation due to low hemoglobin are not well defined. We analyzed in a large cohort of returning donors the prognostic value of RBC parameters and serum ferritin regarding low hemoglobin levels at the subsequent visit. Between 2004 and 2009, RBC indices and serum ferritin were recorded in 45,533 visits by 7,994 donors. In 689 instances, donation was deferred at the subsequent visit due to low hemoglobin levels (<123 g/l for female donors, <133 g/l for male donors). Pre-donation hemoglobin at the current visit correlated best with hemoglobin at the subsequent visit (R (2) = 0.63), whereas other RBC indices and serum ferritin correlated only poorly (R (2) ≤ 0.15). Similar results were obtained in ROC curve analysis and in multivariable binary logistic regression. A pre-donation hemoglobin within 5 g/l from the deferral threshold (<128 g/l for female, <138 g/l for male donors) predicted below-threshold hemoglobin levels at the subsequent visit with a sensitivity of 52% and a specificity of 94%. In conclusion, pre-donation hemoglobin is a useful marker identifying donors at risk of developing low hemoglobin levels. Diagnostic and therapeutic interventions should be aimed at donors presenting with hemoglobin levels near the threshold of donor deferral.