[Suzuran]

The screening isn't just for safety, it's for biological compatibility with the recipient - a mismatched organ will not function and will be destroyed by the recipient's (even suppressed) immune system. It's worse than just failing, you damaged the recipient and you wasted an organ that could have gone to a proper match. When I received my kidney transplant I had to acknowledge a risk of contracting an undetected bloodborne illness from the (deceased) donor's history of drug usage. If the primary concern driving screening was simply safety the organ would not have been considered available. The primary concern is compatibility. Other resulting conditions can be managed afterward. The risk of me dying as a result of the aforementioned undetected bloodborne illness was some tiny fraction of a percent - The risk of me dying on extended dialysis is one hundred percent.