Table 1.
Comparison of CGM Systems
| Feature | FreeStyle Libre 14-Day (6) | FreeStyle Libre 2 (7) | Dexcom G6 (8) | Medtronic Guardian 3 (9) |
|---|---|---|---|---|
| Type of system | isCGM | isCGM | rtCGM | rtCGM |
| Calibration required? | No | No | No | Yes (at least two daily) |
| Glucose data display options | Receiver or smartphone (requires scanning sensor to display glucose data) | Receiver or smartphone (requires scanning sensor to display glucose data) | Receiver or smartphone (continuous) | Smartphone (continuous) |
| Glucose data storage | Measures glucose every minute; stores data every 15 minutes (requires scanning to upload last 8 hours of data to receiver or smartphone) | Measures glucose every minute; stores data every 15 minutes (requires scanning to upload last 8 hours of data to receiver or smartphone) | Stores data every 5 minutes to receiver or smartphone (if within range of device) | Stores data every 5 minutes (if smartphone is within range of device) |
| Range of transmission between sensor and receiver or smartphone | Not applicable | 20 feet (unobstructed) to receive alerts/alarms only | 20 feet (unobstructed) | 20 feet |
| Sensor wear time, days | 14 | 14 | 10 | 7 |
| Warm-up time, hours | 1 | 1 | 2 | up to 2 |
| Glucose display range, mg/dL | 40–400 | 40–400 | 40–400 | 40–400 |
| Remote monitoring options | LibreView: Cloud-based software with real-time data for smartphone users; LibreLinkUp: real-time data-sharing with smart device | LibreView: Cloud-based software with real-time data for smartphone users; LibreLinkUp: real-time data-sharing with smart device | Dexcom Clarity: Cloud-based software with 45-minute delay of glucose data; Dexcom Share: real-time data-sharing with smart device | CareLink: Cloud-based software with real-time data (uploaded every 24 hours from personal to professional website); CareLink Connect: real-time data-sharing with smartphone |
| Real-time alarm for glucose thresholds? | No | Yes | Yes | Yes |
| Predictive glucose alerts? | No | No | Yes | Yes |
| Reported MARD for outpatient use, % | 9.30 | 9.30 | 9 | 8.7–10.6 |
| Potentially interfering substances | Vitamin C | Vitamin C | Hydroxyurea, acetaminophen >1 g every 6 hours | Acetaminophen |