A nurse is providing teaching to a client who has a new diagnosis of type 1 diabetes mellitus about administering NPH insulin and regular insulin together in one injection. Which of the following instructions should the nurse include?

Rationale: A. Inject into the vastus lateralis: The preferred injection sites for insulin are subcutaneous areas such as the abdomen, upper arms, thighs, or buttocks. The vastus lateralis is used for intramuscular injections, not subcutaneous insulin administration. B. Roll the syringe gently to ensure mixture of the insulins: Only the NPH (cloudy) insulin should be rolled gently between the hands to mix it evenly before drawing it up. The syringe itself should not be rolled after both insulins are inside, as this may affect accuracy. C. Draw up regular insulin prior to NPH insulin: When mixing insulins, regular (clear) insulin should be drawn up first to avoid contaminating the vial of regular insulin with the cloudy NPH insulin, which could alter its action and absorption. D. Use a 15 angle for the injection: Insulin is administered subcutaneously using a 45- to 90-degree angle, depending on the client’s body habitus. A 15-degree angle is too shallow and is used for intradermal injections, not subcutaneous ones.