Types of continuous glucose monitors

There are currently two companies that manufacture continuous glucose monitors (CGMs) approved for use in people with type 1 and type 2 diabetes in the US. Dexcom markets the G4 PLATINUM and Medtronic markets three products, including two CGMs that are part of integrated CGM-insulin pump system (the MiniMed Paradigm REAL-Time Revel system and the MiniMed 530G With Enlite), and a stand-alone CGM (the Guardian REAL-Time).

Important features of CGMs to consider

The CGM marketplace is a rapidly changing and evolving one, with new innovations to existing products and new products entering the market every year. CGMs are useful in indicating your glucose trends, such as whether it is going up or down and how rapidly the change is happening. There are several important features of CGMs that you should be aware of if you are considering using a CGM. These include1:

Range.The transmitter in your CGM relays information using a wireless signal from the sensor under your skin to a receiver that you either wear (within an insulin pump as with the Medtronic MiniMed Paradigm REAL-Time Revel system) or carry. Available CGMs have different wireless ranges and if you get out of range the receiver will no longer pick-up and record readings. The range of the wireless signal is important, especially if the receiver will be separated from you, such as with a child who may not be carrying the receiver on his or her body.

Sensor duration. The glucose sensor that is placed just under your skin must be replaced regularly and recommended replacement times range from 3 to 7 days. It is important to follow the manufacturer’s instructions for replacement of the sensor, as the patch that covers the sensor can wear out and begin to peel off. Additionally, a glucose sensor that is left in too long can cause irritation and start to produce unreliable glucose data.

Interface with insulin pump. Currently, the Medtronic MiniMed Paradigm REAL-Time Revel system and the MiniMed 530G With Enlite are the only FDA approved systems that integrate a CGM with an insulin pump. In the near future, other integrated systems will be entering the market.

Overview of available models

The following profiles a selection of CGMs marketed by manufacturer. (Information on prices and product features taken from Diabetes Forecast CGM: Consumer Guide 2014.)

DexCom
DexCom (1-888-738-3646, dexcom.com) manufactures and markets the Dexcom G4 Platinum CGM. The Dexcom G4 Platinum features a built-in alarm that alerts the user when glucose rises above a threshold that can be set by the user..The sensor must be replaced after 7 days. The range of the receiver is 20 feet (from sensor). The sensor only is waterproof up to 8 feet deep for 24 hours.

Medtronic
Medtronic Diabetes (1-888-350-3199, medtronicdiabetes.com) manufactures and markets three CGMs, including the Guardian Real Time, the MiniMed Paradigm Real-Time Revel, and the MiniMed 530G With Enlite.

Guardian Real-Time.
The Guardian Real-Time is a stand-alone CGM (not integrated with an insulin pump), with programmable alarm that can be set to alert the user up to 30 minutes before glucose reaches an upper or lower limit or when glucose is rising or falling rapidly. The sensor (and transmitter) are waterproof to a depth of 8 feet for 30 minutes. The sensor must be replaced after 6 days. The range of the receiver is 6 feet (from sensor). There is a Guardian Real-Time model approved for pediatric use.

MiniMed 530G With Enlite.
The MiniMed 530G With Enlite is fully integrated system that features a continuous glucose monitor with insulin pump. The system features an programmable alarm that can be set to alert the user up to 30 minutes before glucose reaches an upper or lower limit or when glucose is rising or falling rapidly. The sensor (and transmitter) are waterproof to a depth of 8 feet for 30 minutes. The sensor must be replaced after 6 days. The range of the receiver is 6 feet (from sensor). The MiniMed 530G is not approved for use in children.

MiniMed Paradigm Real-Time Revel.
The MiniMed Paradigm Real-Time Revel is a fully integrated system that features a CGM with insulin pump. The system features a programmable alarm that can be set to alert the user up to 30 minutes before glucose reaches an upper or lower limit or when glucose is rising or falling rapidly. The sensor (and transmitter) are waterproof to a depth of 8 feet for 30 minutes. The sensor must be replaced after 3 days. The range of the receiver is 6 feet (from sensor). The MiniMed Paradigm Real-Time Revel is approved for use in children.

Written by: Jonathan Simmons | Last reviewed: May 2014.
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