Evaluating the Accuracy of Continuous Glucose-Monitoring Sensors
Open accessAbstract
OBJECTIVE—The objective of this study was to introduce continuous glucose–error grid analysis (CG-EGA) as a method of evaluating the accuracy of continuous glucose-monitoring sensors in terms of both accurate blood glucose (BG) values and accurate direction and rate of BG fluctuations and to illustrate the application of CG-EGA with data from the TheraSense Freestyle Navigator. RESEARCH DESIGN AND METHODS—We approach the design of CG-EGA from the understanding that continuous glucose sensors (CGSs) allow the observation of BG fluctuations as a process in time. We account for specifics of process characterization (location, speed, and direction) and for biological limitations of the observed processes (time lags associated with interstitial sensors). CG-EGA includes two interacting components: 1) point–error grid analysis (P-EGA) evaluates the sensor’s accuracy in terms of correct presentation of BG values and 2) rate–error grid analysis (R-EGA) assesses the sensor’s ability to capture the direction and rate of BG fluctuations. RESULTS—CG-EGA revealed that the accuracy of the Navigator, measured as a percentage of accurate readings plus benign errors, was significantly different at hypoglycemia (73.5%), euglycemia (99%), and hyperglycemia (95.4%). Failure to detect hypoglycemia was the most common error. The point accuracy of the Navigator was relatively stable over a wide range of BG rates of change, and its rate accuracy decreased significantly at high BG levels. CONCLUSIONS—Traditional self-monitoring of BG device evaluation methods fail to capture the important temporal characteristics of the continuous glucose-monitoring process. CG-EGA addresses this problem, thus providing a comprehensive assessment of sensor accuracy that appears to be a useful adjunct to other CGS performance measures.
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Accuracy of CGM should be assessed from three viewpoints: the analytical viewpoint, clinical accuracy, and accuracy of the trend.
“Other authors have emphasized the need to assess accuracy from 3 viewpoints: the analytical viewpoint (i.e., evaluation of deviations between CGM values and blood glucose concentrations measured with a suitable comparator), the clinical accuracy, and the accuracy of the trend (i.e., the characterization of deviations between the glucose concentration rate of change and blood glucose concentrations”
From Importance of FDA-integrated continuous glucose monitors to ensure accuracy of continuous glucose monitoring (2025) · cites this paper as [30]
The continuous glucose-error grid comprises a point-error grid analysis for blood glucose measurement accuracy and a rate-error grid analysis for prediction capability.
“Because CGM systems also provide information on glucose fluctuations, the continuous glucose-error grid (CG-EGA) has been introduced comprising of (1) a point-error grid analysis (P-EGA) that evaluates the sensor accuracy in terms of accurate blood glucose measurements; and, (2) a rate-error grid analysis (R-EGA) that assesses the prediction capability of the sensor.77”
From Biocompatible Materials for Continuous Glucose Monitoring Devices (2013) · cites this paper as [77]
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- Authors
- Kovatchev, B. P., Gonder-Frederick, L. A., Cox, D. J., & Clarke, W. L.
- Affiliations
- University of Virginia Health System (US)
- Venue
- Diabetes Care
- Publisher
- American Diabetes Association
- Published
- 2004-08-01
- Volume
- 27
- Issue
- 8
- Pages
- 1922-1928
- ISSN
- 0149-5992 (ISSN-L)
- 1935-5548
- OpenAlex
- W2116146322
- Cited by
- 312
- References
- 13
- Citations by year
- 2026: 8 · 2025: 10 · 2024: 11 · 2023: 7 · 2022: 5 · 2021: 8 · 2020: 9 · 2019: 12 · 2018: 12 · 2017: 13 · 2016: 10 · 2015: 15 · 2014: 15 · 2013: 26 · 2012: 23
- FWCI
- 8.89
- Type
- journal article
- Language
- en
- Open access
- bronze
- doi.org
- Locations
- Diabetes Care (publishedVersion)
- PubMed (publishedVersion)
- Funders
- National Institutes of Health (5r01dk051562-23)
- National Institute of Diabetes and Digestive and Kidney Diseases (R01DK 51562, RO1 DK 51562)
- Topics
- Health Sciences › Medicine › Endocrinology, Diabetes and Metabolism › Diabetes Management and Research
- Health Sciences › Medicine › Endocrinology, Diabetes and Metabolism › Hyperglycemia and glycemic control in critically ill and hospitalized patients
- Health Sciences › Medicine › Physiology › Clinical Laboratory Practices and Quality Control
- Keywords
- continuous glucose monitoring, sensor accuracy, error grid analysis, blood glucose fluctuation, hypoglycemia detection, time delay, self-monitoring of blood glucose
- MeSH terms
- Adult, Aged, Blood Glucose, Clinical Trials as Topic, Diabetes Mellitus, Type 1, Female, Humans, Male, Middle Aged, Reproducibility of Results, Monitoring, Ambulatory
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