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Continuous Glucose Monitoring Systems Comparisons

    Dexcom
Seven
           Freestyle
Navigator
           Medtronic
Guardian RT




Dexcom
Seven

Pros

Cons
Compact sensor/transmitter with excellent skin adhesion
+ Virtually no skin irritation
+ Lowest system start-up cost (~ $800)
+ Lowest per-day sensor cost (~ $5/day)
+ Reasonable accuracy (+/~15%)
+ Free 1-time replacement of system components (within 1-yr warranty)
+ Avg. sensor life 12-14 days
+ Flexible calibration times
+ Very loud alarm (vibrates prior to alarm)
+ Large, well-lit screen
–  Must charge receiver every 3-5 days
Limited options for high/low alarms
Data spikes w/acetaminophen
On-screen data update every 5 minutes
Cannot scroll back in time to specific data points
Download to PC is time-consuming; low quality graphics
Very loud alarm
Sensor insertion requires some practice
No data collection when out of transmitter range





Freestyle
Navigator

Pros

Cons
Best overall accuracy (+/~14%)
+ On-screen data updates every minute; shortest data lag time
+ Detailed on-screen analysis w/stats
+ Many trend graphs w/ scroll-back feature
+ Separate target BG and alarm ranges
+ Meter built into display/receiver
+ Highly customizable high/low alerts and predictive alerts
+ Greatest transmitter signal range
+ Nothing to charge; all disposable batteries
+ Fewest calibrations required (4 per 5 days)
+ Avg. sensor life 7-10 days
+ Simplest sensor insertion process
–  Bulky sensor/transmitter
Poor Skin adhesion; extra tape often needed
Perpendicular sensor may cause irritation in lean individuals
10-Hour warm-up period with each sensor startup
Repeated alarms with high & low glucose levels may be a nuisance
On-screen text difficult to read without backlight
Must go through several menus to get to trend graphs
Highest start-up cost (~ $1200) and per-day sensor cost (~ $9/day)
Calibration times require scheduling
Must use Freestyle strips for calibrating
May only calibrate when BG stable & within specified range




Medtronic
Guardian RT

Pros

Cons
Does not require separate monitor (if using compatible insulin pump)
+ Compact sensor/transmitter
+ FDA-approved for children
+ Re-usable sensor insertion device
+ Data downloadable to online program; detailed analysis & excellent graphics
+ Can scroll through specific data points on trend graphs
+ Transmitter “remembers” last 40 minutes of data if out-of-range of receiver
+ Predictive alerts (Guardian model)
+ Reasonable per-day sensor cost (~ $6)
–  Poorest overall accuracy (+/~ 19%)
Avg. sensor life 4-6 days
Sensor/transmitter requires tape covering
Alarms may go unnoticed
Transmitter requires charging at least every 6 days
Stops showing data if calibration missed
Relatively small screen
Requires sensor change/restart every 3 days
On-screen data update every 5 minutes
Requires 2-3 calibrations per day
Should not use “Link” meter with pump when sensor is in use
Effective sensor insertion is highly technique-dependent
May only calibrate when BG stable & within specified range
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