Continuous glucose monitoring systems or CGM provide a more convenient alternative to typical glucose monitoring devices that compel diabetes patients to prick their skin a couple of times every day. These use a circuit of devices that is connected to a sensor inserted under the skin to continuously gather records of blood glucose values. CGM basically records fluctuations in blood glucose levels on a constant basis to determine whether changes in the diet, medication, treatment, or physical activity are needed.
CGM has three components: a sensor, a transmitter, and a pager-like wireless monitor. The sensor is inserted under the skin, usually in the upper arm, near the thighs, and under the abdomen, to measure glucose levels of the tissue fluids. People who are using insulin injections, insulin pens, and insulin pumps have no problem finding these sites as these are basically the same. It should be noted that sensors should be placed two inches away from the navel and should not be placed over bruised, swollen, and tender skin. Placing the sensor is usually quick and relatively painless.
A transmitter is hooked to the sensor and sends information every ten seconds or so via radio waves to a pager-sized monitor, which then displays blood glucose values. The transmitter of a CGM is rechargeable and should be recharged every few days. This is water resistant and does not need to be removed during bathing, exercising and swimming.
CGM comes with an alarm system. This alerts the patient whenever blood glucose levels go below or above the set threshold.
CGM is replaced every three to seven days, depending on the brand and manufacturer. After which, all the data recorded in its built-in memory are downloaded to a computer. This information will be analyzed and charts and graphs will be produced to represent the trends in the fluctuations of blood glucose levels.
Although the results recorded by the CGM are accurate, these should still be checked with a blood glucose monitors or glucometers from time to time for calibration.
Advantages of using CGM
While CGM does not guarantee very accurate readings and is fairly expensive, many patients still opt to use this device because it allows constant monitoring of blood glucose levels without having to prick the skin to draw blood samples. Once the monitor is attached to the patient, continuous readings can be obtained.
Another advantage of using a continuous glucose monitoring system is that fluctuations as well as trends in glucose levels are identified more constantly. Also, this system can possibly record changes in blood glucose that are easy to be overlooked when using glucometers and other tests. For example, CGM can detect dangerous changes in blood glucose levels overnight, in between meals, in the morning, during and after exercise, after every meal, and during a 7-hour time span. Information gathered around these hours can provide health care providers with critical information that will help them decide whether there is a need for a change in treatment, medication and lifestyle.
Disadvantages of using CGM
The CGM system is not yet perfected. Thus, inconsistencies with the records are very common. In order to resolve this problem, users often calibrate their CGMs with blood glucose meters.
CGM is not a replacement to glucometers. Although it can display blood glucose values continuously, glucometers still provide more accurate readings.