Why is blood sugar checked at home?

Home blood sugar (glucose) testing is an important part of controlling blood sugar. One important goal of diabetes treatment is to keep the blood glucose levels near the normal range of 70 to 120 mg/dl before meals and under 140 mg/dl at two hours after eating. Blood glucose levels are usually tested before and after meals, and at bedtime. The blood sugar level is typically determined by pricking a fingertip with a lancing device and applying the blood to a glucose meter, which reads the value. There are many meters on the market, for example, Accu-Check Advantage, One Touch Ultra, Sure Step and Freestyle. Each meter has its own advantages and disadvantages (some use less blood, some have a larger digital readout, some take a shorter time to give you results, etc). The test results are then used to help patients make adjustments in medications, diets, and physical activities.

There are some interesting developments in blood glucose monitoring. Currently, at least three continuous glucose sensors are approved in the United States (Dexcom, Medtronic and Navigator). The new continuous glucose sensor systems involve an implantable cannula placed just under the skin in the abdomen or in the arm. This cannula allows for frequent sampling of blood glucose levels. Attached to this is a transmitter that sends the data to a pager-like device. This device has a visual screen that allows the wearer to see, not only the current glucose reading, but also the graphic trends. In some devices, the rate of change of blood sugar is also shown. There are alarms for low and high sugar levels. Certain models will alarm if the rate of change indicates the wearer is at risk for dropping or rising blood glucose too rapidly. The Medtronic version is specifically designed to interface with their insulin pumps. However, at this time the patient still must manually approve any insulin dose (the pump cannot blindly respond to the glucose information it receives, it can only give a calculated suggestion as to whether the wearer should give insulin, and if so, how much). All of these devices need to be correlated to fingersticks for a few hours before they can function independently. The devices can then provide readings for 3-5 days.

Diabetes experts feel that these blood glucose monitoring devices give patients a significant amount of independence to manage their disease process; and they are a great tool for education as well. It is also important to remember that these devices can be used intermittently with fingersticks. For example, a well-controlled patient with diabetes can rely on fingerstick glucose checks a few times a day and do well. If they become ill, if they decide to embark on a new exercise regimen, if they change their diet and so on, they can use the sensor to supplement their fingerstick regimen, providing more information on how they are responding to new lifestyle changes or stressors. This kind of system takes us one step closer to closing the loop, and to the development of an artifical pancreas that senses insulin requirements based on glucose levels and the body's needs and releases insulin accordingly - the ultimate goal.