What are the drawbacks?
Firstly, the sensor measured glucose in the interstitial fluid rather than the blood (like traditional blood glucose testing). This is the fluid under the skin that sits between the cells.
Glucose changes in the interstitial fluid are slower than those in the blood, so low blood sugar levels (hypoglycaemia) may not be detected quickly enough if levels fall very rapidly.
So for some people, there may still be a need for finger prick tests at times if they feel more unwell than their glucose readings suggest.
The second and biggest problem is cost. Even the most simple machine (with no means of giving or adjusting insulin) costs over £1,200 in the first year for the machine and sensors, with costs of up to £4,500 a year for the more advanced models.