Pickup said that the technique is accurate when measuring the glucose level in a blood sample, but unknown factors have caused the electrode to get two different readings when simultaneously used inside the body and on a sample of blood. The principle behind this technique is that certain fluorescent molecules bind to specific parts of glucose molecules. The degree of fluorescence changes when glucose is bound. Measurements can then be made by probes inserted under the skin. According to Pickup, near infrared spectroscopy is the most studied non-invasive technique.
Tissues are transparent to light in a certain region of the light spectrum.
Using light in this region, glucose levels can then be measured without puncturing the skin. Pickup noted that a lot of research still has to be done before any of these techniques can be used.