The Painless Glucose Check

This week I had a patient somewhat shyly remark, “ I heard somewhere there is a meter being developed that can check your blood sugar without finger sticks? Do you know how I can get one of those?”

It is a question I get every now and then, and it forces me to check in again with the market to see if a new type of glucose-testing device has slipped in without my knowing. For those of you involved in the world of diabetes it is obvious that, aside from the hope of a closed-loop device, a glucometer that measures glucose without the pain of a stick is the next most desirable piece of technology. And having tested my own glucose by finger stick 6-8 times a day during the latter months of my mild gestational diabetes, I can quite agree that those fingers get sore fast (sheesh)! I have had many patients say that the glucose testing is far more painful than administration of insulin, and they wish every day the finger sticks can be eliminated.

Regular glucose checks are the foundation of good diabetes care (self-care and monitoring overall), and are absolutely integral to my being able to make educated adjustments to diabetes regimens. Hemoglobin A1C is fabulous and the al-time best lie detector, but it doesn’t give any info about day-to-day and hour-to-hour variations that need fine-tuning. There are also other aspects of finger sticks besides the pain that make it less than desirable, including the cost of supplies that need constant replenishment and the need for appropriate disposal of sharps and blood-containing equipment.

In attempts to get around one of the main reasons for poor compliance with diabetes self-monitoring, several companies now offer glucometers that allow for testing on alternative sites such as the forearm. The Freestyle was the first to be specifically designed for alternative site testing but now several other meters have been marketed in this arena including some types of Accucheck, Ascencia and Track Ease meters. Among my clinic patients alone, it has increased compliance somewhat but I have not seen any miracles yet.

The Glucowatch Automatic Glucose Biographer, launched several years ago was slated to be the Great Hope. This device, initially made my Cygnus Inc of Redwood City, CA and FDA approved in 2001, was exactly what my patient asked about: it was able to make glucose measurements without finger sticks and through the skin. How? The watch measured glucose non-invasively by measuring levels in fluid drawn through the skin into gel discs inside the watch. It required an initial calibration (as do many CGMS monitors as well) and a warm up period, and was able to continuously take readings every 20 minutes during a 12-hour period.

Okay, I am sounding a bit lukewarm about this device so you already know it wasn’t a blockbuster. Right you are. The GlucoWatch never quite got off the ground as the liberator from finger sticks that it was hoped to be. The main problem lay in the fact that the glucose readings could be delayed by several degrees versus blood glucose levels recorded by finger stick. So by the time the GlucoWatch made a reading of 250 mg/dL, the finger stick reading could be several points higher or lower and warrant an entirely different action than would be indicated by the GlucoWatch. The watch ended up being used mainly for nighttime hypoglycemia monitoring (it had an alert feature built into it for severe highs and lows), especially in children. But for adults on a day-to-day basis it simply did not fit the bill of what was optimal in self -monitoring. To my knowledge there is no other approved non-invasive testing device on the market as this time.

So I had a sober conversation with my patient in clinic. I told her about the GlucoWatch Biographer and explained it wasn’t quite right for her situation. There are no other liberators-from-the-finger-stick available right now aside from CGMS devices, which are certainly not in the non-invasive group. So she shook her head from side to side and said, “Just thought I would ask.” Hopefully within the next few years this conversation can go differently—it’ s about time for some GlucoWatch offspring to make an entrance.