Deferrals of volunteer stem cell donors referred for evaluation for matched-unrelated stem cell donation.

To minimize donor risk and maintain public support, volunteer donor stem cell donation, whether by mobilized leukapheresis or marrow aspiration, requires careful donor eligibility assessment. Many contraindications to stem cell donation exist, yet analyses of donor deferral rates are not available. In a 36-month series encompassing 2493 potential stem cell donors, we analyzed frequencies and reasons for deferrals. All were presumed eligible by their registries because of previously submitted structured health questionnaire and formal telephone interviews. After assessment by our center's physicians, 3.3% of donors proved ineligible, but 5.6% more were eligible for only one of the collection methods. Higher deferral rates were associated with female sex, increasing age and mobilized stem cell donation vs marrow. Exclusion criteria were identified with approximately similar frequency by medical history, physical examination and laboratory testing. Reasons for deferrals almost exclusively served to protect donor safety; the rare recipient-directed safety concerns could be, and often were, overridden in agreement with the transplant center. As formal analyses have shown, with careful assessment, stem cell donation is acceptably safe, but the plethora of deferral reasons mandate that only physicians with specific experience should evaluate stem cell donors, that is, this task should not be delegated to paramedical personnel.