Continuous glucose monitoring (CGM) is a method of monitoring blood glucose levels through the use of a thin wire sensor placed just under the skin, which samples glucose levels every few minutes throughout the day. The information is transmitted to a device that enables the user to view the information in real time. The data is useful for individuals with diabetes who need to constantly monitor glucose readings in order to prevent dangerous highs or lows. CGM data is also stored for later upload to a computer to help evaluate trends and make treatment optimization.
Why Is It Important To Monitor Blood Glucose Levels?
Many people with diabetes may not have noticeable symptoms until their blood glucose levels are either too high or too low. Hyperglycemia occurs when blood glucose levels are too high. If left untreated, this can lead to more serious complications, such as ketoacidosis.
Alternatively, hypoglycemia occurs when blood glucose levels are too low. If hypoglycemia is left untreated, the individual may experience a seizure or lose consciousness. Blood glucose levels must be controlled in order to avoid serious complications of diabetes.
Monitoring Blood Glucose Levels With a Standard Blood Glucose Meter
The most traditional method of checking blood glucose levels is through the use of a small lancing device to prick the tip of the finger to obtain a drop of blood. The blood sample is inserted into a blood glucose meter, which then measures glucose levels. These meters provide a single data point in time, and are effective for many individuals with diabetes when used several times per day, including before and after meals. For individuals who may need to test their glucose levels more often, CGM may offer an easier and more effective solution than finger sticks alone.
Monitoring Blood Glucose Levels with a CGM
Continuous glucose monitoring is a blood glucose monitoring method that can provide more than 250 readings per day. Minimal finger-stick readings from a standard blood glucose monitor are still required to double check the CGM device accuracy.
All of these readings together provide a pattern of blood glucose levels that may identify trends. Healthcare providers can use these trends to understand fluctuating glucose levels and how they relate to:
- The kinds of food a patient eats
- The types of activity they do
- Medications and dosages
Trends may also help reveal:
- Fluctuations in glucose levels overnight, which are often undetected
- Blood glucose spikes early in the morning
This information enables healthcare providers to understand the effectiveness of an individual’s current treatment plan, and to make adjustments when needed.
Making Continuous Glucose Monitoring More Convenient
A variety of insulin pumps now integrate with CGM systems, helping reduce the number of devices that have to be carried. Newer models even have bright, color touchscreens like smartphones, making them simple to learn and use.
How Does Continuous Glucose Monitoring Work?
Continuous glucose monitoring uses a sensor that is placed under the skin of the abdomen for up to 7 days. The sensor reads the amount of glucose in the surrounding fluid using an enzyme called glucose oxidase, the same technology used for testing strips.
When glucose in the surrounding fluid interacts with glucose oxidase, the enzyme converts the glucose into hydrogen peroxide. The hydrogen peroxide reacts with platinum inside the sensor that then sends a signal to a transmitter. This signal is converted into a glucose reading.
Who Can Use Continuous Glucose Monitoring?
Individuals with diabetes who may benefit from the use of continuous glucose monitoring include those who:
- Have unexplained extreme highs or lows in glucose levels
- Have a diagnosis of gestational diabetes
- Have consistent high or low blood glucose levels
- Are currently using an insulin pump
Speak With Your Healthcare Provider
Continuous glucose monitoring systems may require extra training and practice to use the device properly. Speak with your healthcare provider and your diabetes management team to learn more about continuous glucose monitoring and to determine whether CGM would be an effective addition to your current diabetes management plan.