The current environment of CGM technologies.

Indirect measurements of glucose measure its effect on other properties. For example, glucose seems to change the resistance of the skin to a radio frequency signal so the Pendra device measures glucose via radio frequency impedance. The Orsense device measures Rouleax formation, a “stacking” of red blood cells in small blood vessels, in response to glucose. The Glucon device indirectly measures glucose by looking at the sound created by tissue expansion when heated rapidly by light.