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.
I stopped donating when they said anyone overseas with the military during the 80s could have mad cow disease from donated beef. Fact. But I guess you can get it from the vax now so it’s no biggy.