I was a phlebotomist and worked in the lab before becoming a nurse and you have no idea how clueless some nurses are on blood collection. It is not their fault because it is something not taught in school and they are lucky if they are properly trained on the job.
If using a butterfly needle and you need to draw a PT or PTT (blue top tube) you must use a no-additive discard tube first to displace the air that is in the tubing of the butterfly needle. If not, the air will cause the blue tube to underfill which will disrupt the 1:9 ratio of sodium citrate to blood and the machine wont run and if it does, the results may not be accurate. Also, they trained us to always use the no-additive tube before the blue tube. Some phlebs are lazy and use the chemistry tube with the gel before the blue but this tube contains a clot activator which can interfere with coagulation tests.
Allow the chemistry samples to clot before centrifuging. Usually this takes 10-15 minutes but for those on blood thinners it may take longer. Electrolytes will be out of wack if you dont. You dont want to wait too long either though. Wait more than an hour and glucose levels will be falsely low. For every hour that serum is allowed to sit on the red cells, glucose levels will decrease by 10%. The cells are metabolically active and continue to exchange nutrients. We had nurses that forgot to send down blood through the tube system all day and wanted us to run the tests as if there would be no problems.
If you are collecting from a line and have to transfer blood from a syringe to the tube, still follow the correct order of draw. Also, never push the blood into the tube. I dont know how many times I have received blood from the floors and the blue top tube was way over filled. The tubes have vacuum so will automatically stop where they should. The other tubes dont matter as much but your blue coag tube MUST be at the black line!
If you are going to mix any tube, mix the lavender EDTA tube used for CBCs! If there is a clot, the lab will reject the sample because it wont be possible to get an accurate blood count. The EDTA is sprayed throughout the tube so it doesnt mix as well as the sodium citrate which is a good amount of liquid and mixes easily with blood. If you're drawing somebody and the blood is coming slow, take the tube out, invert the tube with whatever blood you have in it, and stick it back in and continue filling. If using a butterfly, its easy to invert it while its still filling. No stagnant blood!
If blood is hemolyzed beyond a certain degree, it will be rejected, the test cancelled, and will need to be redrawn. Hemolysis signifies the rupture of RBCs which mean their entire cellular components are now contaminating the serum. Potassium that is intracellular is now extracellular and if the lab were to release those results, the levels would be critically high. Usually, it happens with a hard stick or if the blood was coming slow (the vacuum of the tube caused pressure which destroyed RBCs). If the blood is coming but the flow is iffy, its not a bad idea to draw an extra tube for good luck. You'd be surprised, some tubes from the same patient would be grossly hemolyzed yet others would be clear.
Lactic acid must be collected on ice and sent immediately. If I get a sample and its sitting in a bag of water and mostly melted ice, I would call back and ask when exactly it was drawn. The techs use the ABG machine on these specimens so it is very fragile and time sensitive. After 10 minutes, they were no longer good.
Oh, and if you make a mistake and put someone elses label on a tube, dont put the correct patient's label OVER it and think it will be ok. That is an error and will be rejected. Completely remove the wrong label. If you need to put another label on the tube and its the correct patient already, dont cover the name. The lab will assume you are trying to cover up a mistake. Make sure the new label is under the name of the old. Make sure 2 patient identifiers are on each tube. Name and DOB. I cant count how many times nurses would send unlabeled, misslabed, partially labeled specimens. Then I would call and tell them we needed the sample to be redrawn and they would get mad at me. Some didnt believe they made a mistake and had to see it for themselves!
This one doesnt have an effect on lab values but its something else I remember from my phleb days. When drawing blood cultures, show the bottles to your patient before you draw from them and tell them you just need a little bit of blood to mix with each bottle. If you draw their blood and they see those red filled bottles, they will think you filled the entire bottle with their blood and FREAK.