Continuous Glucose Monitoring: Around-the-Clock Diabetes Management
By Athena Philis-Tsimikas, M.D.Published Jul 28, 2014If you’re living with diabetes, testing your blood sugar levels throughout the day is probably as routine as brushing your teeth. If you have type 1 diabetes, you probably test several times a day, including before and after meals. If you have type 2, you may test every few days or multiple times a day, depending on the severity of your diabetes, whether you use insulin or medications, and your individual health profile. In either case, self-testing is a fast, simple way to determine whether the glucose levels in your blood are acceptable at any given time; if they are too high or too low, you know you need to adjust your diet, activity, or medications accordingly.While the finger-stick test is a great way to get real-time information about your blood sugar, it can only tell you where your levels are at the moment of testing. It can’t provide information between tests or over time, so if your glucose levels suddenly spike every afternoon or drop to dangerously low levels during the night, you have no way of knowing. Data about these types of variations and long-term trends can be vitally important to your physician and your diabetes care team, as it may help them make key adjustments to your treatment plan for optimal management.That’s where continuous glucose monitoring systems come in. By checking your glucose levels continually around the clock while you go about your usual activities, these systems can identify spikes, drops, trends, and patterns that finger-stick tests miss.
Guarding Against What Finger-Stick Tests Miss
Continuous glucose monitoring systems consist of two parts. A tiny device is implanted just under the skin of the abdomen that automatically senses glucose levels about every 10 seconds. It measures the amount of glucose in the interstitial fluid between the tissues around the abdomen, and while this is not as accurate as testing the blood itself, it can provide a very good idea of what is happening with glucose levels. The sensor wirelessly transmits the readings to a pager-sized monitoring device you wear or carry that records the data. You or your physician can then download the information from the monitor to analyze your glucose readings and identify trends or irregularities. In addition, you can track your diet, activity, sleep, medications, and other factors and compare them with the readings to see how they may affect glucose levels.Using this data, you and your care team can determine treatment changes that should be made. Future readings will let you know how well those changes are working, and if further adjustments may be needed.Some systems also have alarms that alert you if your blood sugar level is too high (hyperglycemia) or too low (hypoglycemia). You can adjust your diet, medications, or other factors as needed to bring your levels back to normal. Your physician will most likely instruct you to confirm alerts with a finger-stick test before taking any corrective action, just to ensure the reading is accurate.Even though continuous glucose monitoring systems can provide nearly 300 measurements during a 24-hour period, you still need to perform finger-stick tests as directed by your doctor. By comparing your self-test results with those recorded by your continuous glucose monitoring system, you can ensure they match up and, if necessary, have your monitor calibrated for accuracy.If you think continuous glucose monitoring could be right for you, talk with your physician about your options.Athena Philis-Tsimikas, M.D., is a board-certified endocrinologist and the corporate vice president for the Scripps Whittier Diabetes Institute at Scripps Health in San Diego.
