Dr. Kelso has J.D. sign a release form indemnifying the hospital from responsibility should he contract hepatitis B from the needle stick. This being an on-the-job occurrence, the hospital would bear any and all burden for any resulting illness or injury. Also, had Dr. Kelso read the almost certain occurrence reports, he would have known that the stick was Nurse Roberts' fault and not J.D.'s.
J.D. is worried about contracting hepatitis B, but all healthcare workers are given the hepatitis B vaccine when starting employment, so he really had nothing to be concerned about.
Nurse Roberts draws blood from a patient using a syringe with needle attached. She should have been using a vacutainer system (what Carla is shown using to draw J.D.'s blood in the following scene). This would have prevented the risk of an accidental needle stick.
Elliot Reid tells one of her patients that his "LLD" is elevated after getting results back from a lipid profile. She should have said "LDL" (low-density lipoprotein or "bad" cholesterol).