GLUCUBE measures glucose in the blood, not in the interstitial fluid (on the skin). Glucose measurement on the skin may have a slight delay compared to the actual blood value, which is why GLUCUBE allows you to indicate the blood sugar level at the moment.
When the blood glucose level is stable for a while, the glucose levels in both fluids balance out and match. But since the composition of the interstitial fluid depends on the exchanges between the cells in the tissue and the blood, when there are fluctuations in blood glucose, there is a delay of the interstitial fluid compared to the capillary fluid of about 5-10 minutes.
In addition, there is no need to use sensors or patches or to replace any components periodically.