Using Dexcom ONE in the Long Run

How accurate is my Dexcom ONE compared to my blood glucose meter?

Last Updated · August 5, 2022

Dexcom CGM systems provide much more information for users than traditional Self-Monitoring of Blood Glucose (SMBG) does. For Dexcom ONE users, the expected level of accuracy is based on comparisons to fingerstick results--which require careful consideration of timing and technique consistency when drawing blooding glucose values.

Here are the accuracy performance characteristics* of the Dexcom ONE system:

  Adults * Pediatric*
Overall Accuracy: 
Mean ARD% (MARD), 40–400 mg/dL (% average absolute error versus reference across all glucose levels)
9.8% 7.7%
Accuracy Over Time: Mean ARD% (MARD), 40–400 mg/dL    
Day 1: 8.6% 10.5%
Day 2: 8.7% 7.8%
Days 4–5: 10.7% 7.2%
Day 7: 10.6% 6.2%
Day 10: 10.6% 7.1%

Clinical Accuracy:
% of readings that were in the Clarke Error Grid (CEG) A Zone [% CEG A+B Zone]

92% [100%] 96% [99.8%]


Reference: Shah VN, et al. Diabetes Technol Ther. 2018;20(6):428–433.

* Reference is YSI (Yellow Springs Laboratory Instrument)

5-step learning journey

Discover education resources, organised in a 5-step journey, to learn key information about your Dexcom ONE CGM system, from getting started, your first 10 days, to using Dexcom ONE in the long run.

Step 1: The basics of CGM
Step 2: Getting started
Step 3: Your first 10 days
Step 4: Using Dexcom ONE in the long run
Step 5: Understand your Diabetes trends