Hemolysis starts at the time of draw, not in the lab. When we see that bright red, transparent plasma or serum layer, it usually means red blood cells were destroyed before the sample ever made it to the analyzer. That breakdown releases hemoglobin into the plasma, which can throw off tests for potassium, LDH, AST, bilirubin, and more. Common causes at the time of draw: • Using too small of a needle (too much suction = RBC trauma) • Pulling the syringe plunger too fast • Shaking the tube instead