I hope you'll indulge a follow-up question, as to whether Mayo Clinic Blood Donor Program shares a different and related deferral policy my local blood bank just revealed:

After a great deal of pondering of patients like me, who are on hormone ablation therapy for latent prostate cancer, and a lot of discussion, my blood bank permitted my resuming donation for several years. @colleenyoung's help was instrumental.

But, at the latest donation, the screener asked "What is that?", and I explained that adjuvant radiotherapy had caused cumulative damage to my bladder, such that I had to have trigonal bladder resection and construction of an ileal conduit, i.e., urostomy surgery, and "that" is my urostomy bag. A week later, I was informed that the blood bank's medical director declares that donors with urostomies, colostomies, or similar surgery are an impermissible infection risk. Therefore, I may not donate blood, for life.

I'm not a urologist (and I'm pretty sure my blood center's medical director isn't, either), but would guess there is room for doubt about this policy's wisdom. What is Mayo Clinic Blood Donor Program's policy on this matter, and why?