Which type of insulin should be drawn into the syringe first when mixing insulins?

When mixing insulins, the correct practice is to first draw up regular insulin into the syringe. Regular insulin, which is a short-acting insulin, has a clear formulation and should be drawn before any intermediate or long-acting insulins, such as NPH, which is cloudy. The reason for this sequence is to avoid contaminating the clear insulin with any particles from the cloudy insulin.

If the cloudy NPH insulin were drawn up first, there is a risk that the NPH could contaminate the vial of regular insulin, which should remain clear to maintain its efficacy. By drawing regular insulin first, health care providers help ensure that proper dosing and insulin action are maintained, preventing any inadvertent changes in the potency and effectiveness of the insulins being used. This practice is crucial for managing a patient's blood glucose levels effectively without introducing the risk of inaccurate dosing due to contamination.