Medical Encyclopedia
Will my insurance cover the cost of a CGMS?
Depending upon your individual insurance policy most plans will cover the cost if it is being used for a trending test by your doctor. That is, you are hooked up to a CGMS for 3 days to determine trends as part of your treatment plan but do not keep the device.
CGMS testing for diagnostic purposes is also currently reimbursed by Medicare.
You will need to contact your insurance administrator to see if a CGMS is covered for the DexCom STS and MiniMed REAL-Time and Guardian RT systems.
You doctor can, however, prescribe CGMS trending as often has s/he deems it to be medically important.
Both the DexCom STS and Medtronic MiniMed devices are FDA- approved CGMS. The DexCom, however, has received FDA approval for 7-day sensors. This is 4 days longer than the FDA approval for the MiniMed CGM.
Continuous Glucose Monitoring System (CGMS)
Definition: A Continuous Glucose Monitoring System (CGMS) is a medical device that measures and logs blood sugar readings frequently during the day and night. It then averages the blood sugar readings.
While the MiniMed Gold CGMS is intended for use in clinical settings, there are currently three "real time" CGMS available for patients to use on an ongoing, daily basis. Two work alone, while one is an integrated system (works with an insulin pump):
- Paradigm REAL-Time - by Medtronic MiniMed; system uses MiniLink Transmitter CGMS technology and is the first and only CGMS integrated with an insulin pump.
- Guardian RT - by Medtronic MiniMed); and
- DexCom STS - by DexCom.
Real time systems display results for the user to see and sound alarms when blood sugars are too high or too low. The MiniMed CGMS Gold is not a real-time system and is intended for diagnostic purposes as requested by a doctor.
How do CGMS work?
Using a cannula, a small "sensor" is inserted under the skin. The sensor is 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. In real-time systems this information is also displayed for the patient to see. The monitor then averages blood sugar readings 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 can CGMS do for me?
CGMS 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).
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:
It does not administer insulin.
CGMS are valuable tools for learning trends, but they do not replace finger sticks.
You need wear to a separate cannula from an insulin pump cannula.
The cost of transmitters, sensors and other CGMS-related items can average as much as $400 per month (in addition to your test strips and insulin pump supplies).
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).
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.
CGMS are valuable tools for learning trends, but they do not replace finger sticks and require you to wear to a separate cannula.
The cost of transmitters, sensors and other CGMS-related items can average as much as $400 per month (in addition to your test strips and insulin pump supplies).
Continuous glucose monitoring is not the same thing as a closed loop system.
A closed loop system, which is not yet available, would deliver insulin automatically based on readings taken by CGMS sensors. This would mimic the normal function of the pancreas by constantly making insulin adjustments based on current blood sugar readings and history of insulin already delivered.
Summary
There are two non-integrated, "real time" CGMS available: The Guardian RT and the DexCom STS CGMS.
There is one integrated real-time system (MiniMed Paradigm REAL-Time System). Real time systems display results for the user to see and sound alarms when blood sugars are too high or too low.
There is one more CGMS, the MiniMed Gold CGMS, which is not a real-time system and is intended for diagnostic purposes as request by a doctor.