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 just read a report this morning a baby was given blood because of a form of leukemia and died shortly later with blood clots to the heart and brain. You cant blame clots on the baby's own blood since it was "thin" from the leukemia.