Testosterone-Associated Erythrocytosis and Blood Donation: Therapeutic Phlebotomy, Donor Safety, and Recipient Exposure.

Testosterone replacement therapy (TRT) is increasingly utilized and associated with erythrocytosis, leading some individuals to undergo therapeutic phlebotomy or present for blood donation. This emerging intersection between clinical management and blood donation raises important questions regarding donor eligibility, donor safety, recipient exposure, and regulatory oversight. This review examines evidence on testosterone-associated erythrocytosis in the context of blood donation. We review the pathophysiologic mechanisms underlying testosterone-induced erythrocytosis, summarize the current regulatory framework governing therapeutic phlebotomy and donor eligibility, and critically evaluate studies examining donor characteristics, testosterone in blood components, and potential mitigation strategies. The existing donor eligibility regulations do not contain TRT-specific provisions, but blood centers can manage these individuals by first assessing the intent to donate (altruistic or reduction of red cell mass) followed by applying standard donor eligibility criteria, therapeutic phlebotomy policies, and medical director review where appropriate. Available evidence suggests that individuals receiving TRT are increasingly encountered in blood centers and may participate in repeated donations. Laboratory studies demonstrate measurable testosterone concentrations in blood products collected from TRT donors, although the clinical significance of these findings for transfusion recipients remains uncertain. Recent studies also demonstrate that testosterone concentrations in plasma components may be substantially reduced using pathogen reduction technology. However, these observations remain limited to component-level analyses and have not been linked to recipient outcomes. Current evidence is largely descriptive and laboratory-based, highlighting substantial gaps in understanding rather than providing definitive guidance for practice. Additional research is needed to clarify donor risk profiles, determine clinical relevance of hormone exposure in transfusion recipients, and define evidence-based approaches to management of TRT-associated donors within the blood supply.