Red blood cell zinc protoporphyrin to evaluate anemia risk in deferred blood donors.

A large proportion of potential blood donors who are deferred are inappropriate to be donors because of unreliable predonation anemia screening methods. In this study, venous hemoglobin concentrations were within acceptable limits in 71% of 275 anemia deferrals. Red blood cell zinc protoporphyrin (RBC ZP) was evaluated as a screening test to improve the accuracy of detecting anemia in prospective blood donors. The frequency of abnormally low venous hemoglobin concentrations in anemia deferrals having fingerstick capillary microhematocrit (MH) values within 3% of the minimum requirement, together with normal RBC ZP levels (less than 53 micrograms/dL [0.943 mumol/L] RBC), was 2%, and not significantly different from the prevalence of venous anemia observed in eligible blood donors. Anemia deferrals with elevated RBC ZP results had a significantly increased rate of iron depletion and anemia. Capillary RBC ZP measurements in combination with the MH test have the potential to safely decrease inappropriate anemia deferrals.