 This study evaluates the performance and safety of the fluorescence based fibre optic glucose sensor for home usage.24 subjects will take part in the study, including 4 pre-diabetic subjects, 8 Type I diabetic patients, 8 Type II diabetic patients and 4 diabetic patients who require continuous ambulatory peritoneal dialysis CAPD. Type 1, Type 2 and prediabetic subjects will wear one FiberSense sensor, randomly allocated to either the upper arm 50 or abdomen 50 for 28 days. In addition, these subjects will wear a Dexcom sensor on the other side of the abdomen for 7 days in one of the four study weeks. In all 4 CAPD subjects, one FiberSense sensor will be placed in the upper arm for 28 days. No additional comparator sensor will be placed in CAPD subjects. 