The FDA has approved over 20 Continuous Glucose Monitors (CGMs), CGM systems, and senors since 1999. However, most of these approved devices are either combination continuous glucose monitors–insulin pumps, are outdated/earlier versions of improved CGMs (e.g., Dexcom G4 PLATINUM), or CGMs intended for professional use only. Currently, there are only four CGMs on the market that are approved by the FDA as stand-alone Continuous Glucose Monitors. Of these, only Free Style Libre and Dexcom G6® CGM System eliminate the need for fingerstick calibration i.e., do not need to take blood from a finger.
The next best FDA-approved Continuous Glucose Monitors (CGMs) on the market that meet most of the given requirements include Medtronic Guardian Connect and Senseonics Eversense. While both of these CGMs don’t entirely eliminate fingerstick calibration requirements, they are designed to reduce the number of fingerstick calibrations from eight to two calibrations per day.
1. Medtronic Guardian Connect
- The Guardian™ Connect by Medtronic is a stand-alone Continuous Glucose Monitoring (CGM) system that allows users to monitor their blood glucose levels, trends, and alerts on a mobile device.
- Guardian™ Connect measures the blood glucose levels using a sensor that is inserted under the skin. An automatic inserter is used to insert the sensor on the user’s arm or belly. The sensor then measures the “interstitial glucose level, the glucose found in the fluid between the cell.”
- The glucose readings are sent to the Guardian Connect app every five minutes.
- The Guardian Connect system uses Bluetooth Low Energy (BLE) and wireless/cellular data connection. Its transmitter connects with the mobile app via Bluetooth connection. The Guardian Connect app wirelessly sends data to CareLink Personal allowing healthcare partners to access the data from the CareLink website on their computer, smartphone, or tablet.
- The Medtronic Guardian Connect sensor can be worn for up to 7 days.
- While this CGM does not entirely eliminate fingerstick calibration requirements, it reduces the number of fingerstick calibrations to two calibrations per day.
- This CGM is FDA-approved for customers aged 14 to 75. Users in the UK and Ireland can order Guardian™ Connect via the company’s official distributor Pharmed. Users in the United States need a prescription to order the Guardian™ Connect system online.
- The Guardian™ Connect CGM features customizable predictive alerts and predicts glucose levels to alert the user 10-60 minutes before a high or low glucose event with a 98.5% detection rate. Even without the predictive alerts turned on, this CGM has a 90.5% hypoglycemia detection rate.
- It sends glucose readings to the Guardian Connect app every five minutes, giving nearly 288 readings per day.
- It allows users to connect with their healthcare providers using the CareLink™ system platform for remote monitoring.
- The Guardian Connect sensor can be worn for up to 7 consecutive days while its transmitter can last a year.
- Guardian™ Connect CGM allows diabetic users to access and connect with the Sugar.IQ™ diabetes assistant app on their iPhone to monitor and keep track of their glucose levels and assess how their blood glucose reacts to food, insulin, and exercise.
- The Guardian™ Connect transmitter has to be charged before inserting the sensor. Charging takes nearly 2 hours. The fully charged transmitter lasts at least 6 days without needing a recharge.
- The transmitter’s range to send data to a mobile device is 6 meters, which is close to the range between a Bluetooth headset and a phone.
- Users can export reports and data as .xlsx (Excel) file using the “Eversense Data Management System (DMS), a web-based application compatible with the Eversense App” which stores glucose data.
- Guardian™ Connect CGM requires at least two fingerstick calibrations a day, after every 12 hours. To improve accuracy, users are encouraged to calibrate more often by taking blood from a finger.
- Unlike the Dexcom G6® CGM System, this CGM can not be used by customers below the age of 14.
- Setting up this CGM for the first time takes 2-3 hours. After inserting the sensor under the skin, pairing the transmitter, and setting up the mobile app, the sensor takes as much as 2 hours to warm-up. On the other hand, Freestyle Libre takes only 1 hour to warm-up.
2. Eversense CGM
- Eversense CGM by Senseonics is the first long-term implantable Continuous Glucose Monitor in the world. It comes with a sensor, a transmitter, and a mobile app for blood glucose monitoring.
- The sensor is inserted under the skin in the upper arm. A trained health care provider inserts the sensor by making a small incision. The sensor lasts for 90 days.
- The transmitter is placed over the CGM sensor to receive the glucose data from the sensor. This data is then sent to the Eversense Mobile App on the user’s phone or smartwatch via Bluetooth.
- Eversense CGM offers the world’s longest-lasting CGM sensor that can be worn for 90 consecutive days. On the other hand, other CGMs require frequent self-insertions (after every 7 to 14 days).
- Eversense CGM transmitter receives and transmits glucose data every five minutes.
- The CGM transmitter is easy to remove and replace without having to remove the sensor.
- In addition, the CGM transmitter offers on-body vibration alerts when glucose levels are high or low. This feature works even if the user’s mobile is not nearby.
- Users can set separate predictive alerts for the “predicted high glucose alert and the predicted low glucose alert.”
- Eversense CGM app can track workouts and meals and help in identifying trends.
- Eversense CGM app allows users to remotely share their glucose data with five people using the Eversense NOW mobile app.
- This CGM is suitable for continually measuring glucose levels in diabetic adults. Unlike other CMGs, Eversense CGM is not for users under the age of 18.
- While Eversense CGM is “indicated for use to replace fingerstick blood glucose measurements for diabetes treatment decisions,” fingerstick calibrations are still required at least two times a day.
- Eversense CGM sensor can not be self-inserted. A trained healthcare provider performs the implantation and removal of the sensor.
- After the sensor is inserted for the first time, there’s a 24-hour warm-up period. The transmitter can be placed after the warm-up period to start monitoring glucose levels.
- The CGM transmitter has to be removed and recharged daily.
- The company has stopped the commercial sales of Eversense CGM to new customers as a result of the financial repercussions of the COVID-19 pandemic.
Upcoming Non-Invasive CGMs
- While there are only a few Continuous Glucose Monitors (CGMs) that meet the required criteria and are available to buy, a number of non-invasive CGMs are currently under development and can be available in some countries by year-end.
- GlucoWise™ is a CGM device being developed by META. This non-invasive device will monitor “blood glucose levels without the need to pierce the user’s skin.” Its sensor will measure the blood glucose levels every few seconds, or as often required, by gently squeezing the skin between the forefinger and the thumb or the earlobe. GlucoWise™ will then display the readings on the device’s screen.
- It can also send data wirelessly to a smartphone or tablet using the Glucowise app. A cloud-based data management system can further store the historical data.
- While GlucoWise™ is currently under development and is not available for public testing yet, it may potentially appear as a competitor of FreeStyle Libre and Dexcom G6 in the near future.
- sugarBEAT® is another non-invasive CGM currently being developed by Nemaura Medical Inc. This CE marked CGM will likely be available for purchase in the UK and Ireland later this year.