What is CGM?
It is a system that measures sugar levels in the fluid around the cells in your body tissue throughout the whole day. When you test with your blood glucose meter, you are taking a measure of the sugar in your blood. The results from your meter and from CGM are not the same. Sugar moves through the blood first and then into the tissue fluid. This explains the difference between the CGM and meter results.
How CGM works
- A sensor is inserted under the skin and connected to a transmitter.
- The transmitter sends data to a receiver/phone app or insulin pump via radio signal.
- Sensors must be replaced every 7-10 days.
Benefits of CGM
- Helps identify patterns and trends in glucose levels.
- Can reduce A1C and lower frequency of hypoglycemia when used consistently.
- Alarms can alert you to rising or falling glucose levels.
- Useful for adjusting insulin doses and insulin pump settings based on trends.
Limitations
- CGM does not automatically control blood sugar.
- You must still make decisions about insulin doses.
- Not approved for hospital use—hospital meters must be used instead.
- Acetaminophen (Tylenol) can interfere with CGM accuracy.
Costs and coverage
- CGM systems vary in cost.
- Insurance coverage can apply to some of the cost towards a CGM.
- CGM can be covered by ADP if the criteria is met.
- Some CGMs are covered by ODSP, Trillium, OHIP +, and OHIP > 65 yrs.
Useful links
Continuous Glucose Monitor Comparison Table (BETTER Project)