I have had a couple of friends attempt to donate blood recently who were turned away because the machines weren’t able to draw from them.
Tubing issues were blamed first.
Eventually, the staff told them they couldn’t donate because the flow was being blocked by clots.
In both arms.
These people are all under the age of 35, by the way. And were under the impression they had no health issues.
O Neg here too. The thing that sux about being O Neg, is you can donate and literally every person of any culture with any blood type out there can benefit from my (our) blood, but if WE need blood, it HAS to be O Neg. Statistically not many of us around...