Q- What is Continuous Glucose Monitoring Device (CGMD) ?

A continuous glucose monitor is a small device that you wear just under your skin. It measures your glucose (sugar) levels continuously throughout the day and night, letting you see trends in your levels and alerts you to highs and lows. 

A CGM doesn’t actually measure your blood glucose levels, it measures the amount of glucose in the fluid that surrounds your body cells – called interstitial fluid. There is a small time delay when checking this fluid, especially after eating or if you're exercising. So your CGM result isn't always exactly the same as your finger-prick result. This means you'll still need to do a finger-prick test if you’re thinking of changing your treatment at any point, like if you need to take more insulin or if you're treating a hypo, so you can get the most accurate result.

There are two types of CGM:

  • Real time: you can check your sugar levels yourself at any time, as well as being able to download them.
  • Retrospective: you can’t see your sugar levels in real time but you can look back at results by downloading them.

Q- How does CGMD work? 

A CGMD has three parts:

  • A sensor that sits just underneath your skin and measures your sugar levels.
  • A transmitter that’s attached to the sensor and sends your levels to your display device.
  • A display device that shows you your sugar level. This might be a separate hand held device (known as “standalone” CGM) or a pump (known as an “integrated system”).

CGM comes with software so you can analyze your results and see patterns in your sugar levels over time.

You generally wear a sensor for up to seven days, and after that you need to replace it. When you change your sensor, you reattach the transmitter to your new sensor.

You need to calibrate a CGM by checking your finger-prick blood glucose levels, generally twice a day. 

Q- What are the advantages and disadvantages of CGMD?

  Advantages of using CGMD
  Disadvantages of using CGMD
  • You can track your sugar levels all through the day and night.

  • You can see what your levels are like at times when you don’t normally test. 


  • You can take action earlier based on your sugar levels.  

  • It can help reduce the chances of having low blood glucose as you can see a downward trend of your sugar levels. You can set it to alarm at high and low levels.
  • You can get overloaded with data, which can confuse or worry you.

  • You still need to do some finger prick checks.

  • You may find wearing the sensor irritating or unsightly.

  • You need to be motivated to use the data it gives you to get the best diabetes management.

Please watch the below video on " Continuous Glucose Monitoring Device"- 



1. Continuous glucose monitoring (CGM). (2017). Diabetes UK. https://www.diabetes.org.uk/Guide-to-diabetes/Managing-your-diabetes/Testing/Continuous-glucose-monitoring-CGM

2. What is Continuous Glucose Monitoring (CGM. (2019, June 17). What is Continuous Glucose Monitoring (CGM)? YouTube. https://youtu.be/Kw2XP44oEQM