I have recent experience with this. Got a call from Heme lab - rm XXX'S CBC and pt/inr was hemolyzed. We needed to draw a new sample. I happened to be working charge that day, and I didn't remember that patient being on my central line/ PICC list, so I pulled open the chart and verified that yes, in fact, this patient was a lab-draw. After sharing this with the lab person, there was a pause, and the person said, and I quote, "that can't be right. Our samples don't go bad."
So. Yeah, they do. It is not just nurses and CNAs, as you say.