Clinicians at King’s College Hospital, London, are trialling a new continuous glucose monitoring (CGM) system for people with type 1 diabetes that allows them to continuously track their blood glucose levels using a smartphone app, rather than needing to draw blood several times a day.
The sensor, which is manufactured by Senseonics (Germantown, MD, USA), measures glucose levels in the interstitial fluid and, at a size of 3 mm by 16 mm, can be implanted in the upper arm or abdomen, with no part protruding from the skin. The sensor is linked to a transmitter worn outside the body that sends the data via Bluetooth to the user’s smartphone. This allows at-a-glance monitoring of glucose levels, as well as alerts for impending hypoglycaemia or hyperglycaemia.
While other CGM sensors, and indeed fingerprick test strips, use the glucose oxidase enzyme to measure glucose levels, the Senseonics system uses a unique fluorescent, glucose-indicating polymer. A light-emitting diode embedded in the sensor excites the polymer, and the polymer then rapidly signals changes in glucose concentration via a change in light output. This means the sensor can last up to 90 days before needing to be replaced, whereas other sensors currently need to be replaced every 1–2 weeks.
More information on the system can be found at the Senseonics website.
