Iron depletion in blood donors - Have extended erythrocyte and reticulocyte parameters diagnostic utility?

Blood donation is associated with iron depletion, but donor iron status is not usually investigated, as such tests are cumbersome and costly. It would therefore be desirable to have simple, fast and inexpensive tests that give information on a donor's risk of developing iron depletion. In a pilot study we investigated whether novel erythrocyte and reticulocyte parameters can serve this goal.

In regular blood donors extended red cell parameters were measured using the Abbott CELL-DYN Sapphire hematology analyzer and conventional biochemical tests of iron status. Donors were compared with a regionally matched group of non-donating controls.

In the controls, the reference ranges of extended RBC parameters were well comparable to published data. Donors had significantly more microcytic RBC than controls (median 0.9 vs 0.6%), lower serum ferritin concentration (median 43 vs 91 mg/L) and higher soluble transferrin receptor/ferritin index (median 1.60 vs 1.27). Overall 18-28% of the donors were iron depleted. Moreover, 3.3% of donors had iron-restricted erythropoiesis. Microcytic RBC and reticulocyte mean cell hemoglobin content predicted iron depletion with 70% and 64% sensitivities and specificities of 72% and 78%, respectively. When combined these two parameters increased the sensitivity to 82%.

Our results in Swedish blood donors confirm a high prevalence of iron depletion, despite iron supplementation used by about half of the donors. Microcytic RBC and MCHr appeared to be helpful in identifying iron-depleted donors, who might benefit from iron supplementation. We recommend larger prospective investigations in order to confirm and extend the findings of this pilot study.