Medical Encyclopedia
Will my insurance cover the cost of a CGMS?
Depending upon your individual insurance policy most plans will cover the cost of an insulin pump; however, you will need to contact your insurance administrator to see if a CGMS and the necessary supplies are covered.
Unfortunately, the Guardian RT is not available throughout the United States yet. It has been initially introduced in only seven U.S. cities and many patients report trouble getting insurance to cover the device and sensors.
Misconceptions about CGMS Technology
If you think that CGMS replaces the need for finger sticks you would be wrong -- it does not.
Some key points about current CGMS technology include:
- CGMS are valuable tools for learning trends, but they do not replace finger sticks.
- It does not administer insulin.
- You need wear to a separate cannula from an insulin pump cannula.
- The cost of transmitters, sensors and other CGMS related items can cost as much as $400 per month (in addition to your test strips and insulin pump supplies).
Continuous Glucose Monitoring Systems (CGMS)
The Guardian RT, a real-time CGMS
Definition of a Continuous Glucose Monitoring System (CGMS) - a medical device that measures and logs blood sugar readings frequently during the day and night. It then averages the blood sugar readings.
About the Guardian REAL-Time CGMS
The Guardian RT is manufactured by Medtronic MiniMed. It may be covered by some insurance plans and is approved for use in patients of all ages as recommended by their doctor.
This device works just like the MiniMed Gold CGMS, however, unlike the MiniMed Gold, it works in "real time" displaying blood sugar levels every five minutes on a monitor that can be worn on the belt. When blood sugars are too high or too low the user is alerted. This allows the patient to make adjustments in their diabetes care quickly and more accurately.
Key features of the Guardian RT include:
- Predictive Alerts can be set to warn you 5, 10, 15, 20, 25, or 30 minutes before glucose limits have been reached.
- Rate of Change Alerts let you know when your glucose levels are changing.
- Low and High Alerts tell you when you've reached the glucose limits you've set.
- It is a unit separate from an insulin pump and is not integrated with an insulin pump at this time; however, you can get this technology in the MiniMed REAL-Time CGMS that can be integrated with certain Paradigm insulin pumps.
How does the Guardian RT work?
Using a cannula, a small "sensor" is inserted under the skin. The sensor must be placed in the abdomen where it then senses blood sugar (glucose) levels every 10 seconds. The readings are sent via a wireless pager (the CGMS monitor) where the data is recorded. The monitor displays the information for the patient to read and respond to. An alarm sounds if blood sugars are too high or too low.
Important trends in blood sugar fluctuations can be seen as blood sugar readings are taken every 5 minutes for up to 72 hours before the sensor needs to be replaced.
The sensor does not administer insulin and a separate cannula must be worn to infuse insulin from an insulin pump or you will need to continue taking shots.
What the Guardian RT CGMS can do for you
Like the DexCom STS, the Guardian RT can pick up on trends that might otherwise go undetected. For example, CGMS technology can pick up low blood sugar readings during the nighttime when the patient is sleeping. It can also evaluate how a person's blood sugar reacts to exercise, food, illness, etc. Understanding these trends can help your doctor make adjustments in your diabetes care plan to keep you blood sugars under better control while reducing the risk of hypoglycemia (low blood sugar).
Picture of Guardian RT System
Summary of the types of CGMS available in the U.S.
Real time systems display results for the user to see and sound alarms when blood sugars are too high or too low.
There are three real-time systems:
-- Two non-integrated, "real time" CGMS available: The Guardian RT and the DexCom STS CGMS; and
-- One integrated real-time system (MiniMed Paradigm REAL-Time System).
There is also one more CGMS, the MiniMed Gold CGMS, which is not a real-time system and is intended for diagnostic purposes as requested by a doctor.
Things to consider before purchasing the Guardian RT
With CGMS technology you have to calibrate the system with each sensor change and in some cases daily. It will not do away with finger sticks. The sensors on both the MiniMed Gold and Guardian RT systems are only good for up to 72 hours. Both devices don’t begin working for about 2.5 hours after set up and must be calibrated (with a finger stick blood sugar check) at 2 hours after insertion, again at 6 hours after insertion and then every 12 hours afterwards.
Note: The sensors on the DexCom STS have been approved by the FDA for 7 day use.
The FDA warning label on CGMS specifically states not to act (treat lows or take insulin) based on sensor readings but to do a finger stick before acting.
Currently, there is no closed loop system that allows readings from CGMS to calculate and administer insulin accordingly. This still must be done by the patient (although many pumps do have the capability of calculating and recommending insulin doses the patient must still instruct the pump to go ahead and give the insulin).