Real-time glucose sensor (in blue), sitting on the skin surface with its tip inserted in the tissue interstitial fluid, measures glucose levels. The glucose value is transmitted to the insulin pump by radiofrequency, and sensor glucose values, graphs and trend arrows are displayed on its screen. An appropriate insulin dose is calculated based on the glucose value by insulin pump software and can be administered, if approved by the user, through the pump infusion set (in gray) with its catheter in the subcutaneous tissue delivering insulin.