“Most patients don’t realize that the person sticking the needle in their arm today could have been flipping burgers last week,” said Dennis Ernst, a veteran phlebotomist who runs a phlebotomy resource center in Ramey, Ind. The consequences — in mistakes made and injuries to patients — can be dire: contaminated samples that have to be redrawn, false positive results, incorrect medication doses, fractures, nerve damage and worse. And while the great majority of us will never face a blood-draw injury worse than a sore arm, the potential for harm has proven real.