Color-Change Hydrogel Glucose Monitor (image) University of Illinois at Urbana-Champaign Caption Before glucose is added, the hydrogel glucose meter is blue. As the glucose level rises, the color shifts to green, then red. Credit Chunjie Zhang Usage Restrictions None Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.