Here's a story from the MIT Technology Review describing progress at Baylor in non-invasive glucose monitoring.
Quoting from the article, written by Jennifer Chu:
"The sensor itself is a small, spiral-shaped microwave circuit, which acts as a transmission line and emits electromagnetic waves. When a person places her thumb on the spiral, the electrical properties of her thumb change how energy passes through the circuit. Jean and his colleagues measure this change, and in early trials, they seem to have found patterns that correspond to variations in glucose levels."
I hope it works!