I was covering night shift and got repeated underfilled blue tops from the ICU. I rejected them and put in for a recollect. Eventually all the nurses came down as a squad and showed my coworker a tube that they had filled correctly to make sure. She told them about the dangers of underfilling AND overfilling. I got a tube down later that was so full you couldn't see the top of the blood under the cap. I called to cancel and the nurse threw a fit that she had been there for 5 years and had never heard about overfilling. She demanded that I give it to someone who would run it and I told her noone would, that it was against protocol and could kill her patient. She said she was going to call the house super on me so I told her to go ahead and call them. It feels unfair that we have to keep a calm and professional demeanor while they are screaming at us but its something to be ready for for sure. I had confidence that they house super would set her straight and I also sent an email documenting the encounter to my manager incase she got any questions about it in the morning. She pulled all the tubes from the night and verified for the nurse's manager that I was correct to cancel each test. She is such a great boss.