Continuous monitors currently on the market do not directly determine blood glucose levels, they instead read the interstitial glucose.
This fact results in a great issue: the latency with respect to blood glucose.
Blood glucose takes 5 to 25 min. to move into the interstitial fluid
This fact means that the measurements of the continuous monitors on the market do not faithfully represent the current blood glucose levels.
What are the consequences?
Lack of glycemic control
Sudden fluctuations in glucose values occur at various times of the day, this is when the problem of lag is aggravated.
Increased risk of hypoglycemia
The time lag gives us false confidence, we believe that we are in stable values when in fact we are experiencing hypoglycemia or a sudden change in blood glucose.
Need to make insulin corrections
Uncontrolled blood glucose forces us to resort to more doses of insulin, which translates into more injections/punctures.
More glucometer checks
We turn to the glucometer to know reliably how are our glucose levels. Doing that excecibely due to lack of precission, causes us to have bruised fingers.