Non invasive blood glucose measurement

    One of the most important goals of the diabetes industry is to achieve a reliable noninvasive method to monitor blood glucose levels. Existing methods are very efficient in providing an accurate reading, but they still rely on the necessity of piercing the skin to draw a small drop of blood. Some devices allow taking samples from less sensitive areas, such as forearm, upper arm or thigh. So far, no alternative methods have succeeded in completely replacing the traditional blood glucose meters.

Is there hope?

    Of course there is. Scientists have been working out other ways to draw small amounts of fluid from the body without having to puncture the fingertips or other parts with a lancet. The first “non-invasive” glucometer to be approved by FDA is the GlucoWatch G2 Biographer, manufactured by Cygnus Inc. This wristwatch-like device uses a tiny electric current to obtain body fluid from the wrist and measure glucose levels several times every hour for up to 12 hours. The GlucoWatch needs to warm up for about three hours, after which the glucose levels can be read directly from the display. This device is useful to obtain trends and patterns of glucose variations with time and during particular situations such as meals or exercise. This allows detecting more readily episodes of hyperglycemia and hypoglycemia. However, the measurements have to be confirmed by a traditional moniter since the GlucoWatch is not intended as a replacement of the standard glucose meters.
    FDA also approved a “minimally invasive” glucose meter. The MiniMed Continuous Glucose Monitoring System (CGMS) consists of a thin catheter that is inserted just under the skin and continuously collects small amounts of fluid that is then analyzed by a biosensor. The data are stored in a memory device and can be downloaded into a computer or reading device by the user or a care provider. The strength of this devise resides in its ability to provide a continuous monitoring during up to 72 hours. This allows the doctor to get a precise picture about the patient’s glucose profiles and thus to design more effective treatment strategies. Again, the MiniMed CGMS needs to be complemented and calibrated with a standard glucose monitor. Both the GlucoWatch and the MiniMed CGMS have to be prescribed by a doctor.

Future perspectives

    Still in experimental phase, scientists are investigating other potential ways to measure blood glucose levels. Among these new technologies, one of the most promising is based on spectroscopy, a physicochemical principle that allows identifying the chemical composition of a given sample by using light. In this case, the idea consists of a laser beam that penetrates the skin and measures glucose in situ and is completely painless.
Other lines of research include measuring waves of infrared radiation produced by the body, assessing the viscosity of the fluids in the tissue under the skin, using ultrasound to name a few.
    Modern glucose monitors are getting better and better, but it is also true that they are not as comfortable as it could be for some people. Fortunately, new technologies are evolving at a fast pace and the promise of a fully noninvasive monitor is closer than ever.

For more information visit FDA website on diabetes at www.fda.gov/diabetes