The Surveillance Error Grid

Abstract

Introduction: Currently used error grids for assessing clinical accuracy of blood glucose monitors are based on out-of-date medical practices. Error grids have not been widely embraced by regulatory agencies for clearance of monitors, but this type of tool could be useful for surveillance of the performance of cleared products. Diabetes Technology Society together with representatives from the Food and Drug Administration, the American Diabetes Association, the Endocrine Society, and the Association for the Advancement of Medical Instrumentation, and representatives of academia, industry, and government, have developed a new error grid, called the surveillance error grid (SEG) as a tool to assess the degree of clinical risk from inaccurate blood glucose (BG) monitors. Methods:A total of 206 diabetes clinicians were surveyed about the clinical risk of errors of measured BG levels by a monitor. The impact of such errors on 4 patient scenarios was surveyed. Each monitor/reference data pair was scored and color-coded on a graph per its average risk rating. Using modeled data representative of the accuracy of contemporary meters, the relationships between clinical risk and monitor error were calculated for the Clarke error grid (CEG), Parkes error grid (PEG), and SEG.Results: SEG action boundaries were consistent across scenarios, regardless of whether the patient was type 1 or type 2 or using insulin or not. No significant differences were noted between responses of adult/pediatric or 4 types of clinicians. Although small specific differences in risk boundaries between US and non-US clinicians were noted, the panel felt they did not justify separate grids for these 2 types of clinicians. The data points of the SEG were classified in 15 zones according to their assigned level of risk, which allowed for comparisons with the classic CEG and PEG. Modeled glucose monitor data with realistic self-monitoring of blood glucose errors derived from meter testing experiments plotted on the SEG when compared to the data plotted on the CEG and PEG produced risk estimates that were more granular and reflective of a continuously increasing risk scale. Discussion:The SEG is a modern metric for clinical risk assessments of BG monitor errors that assigns a unique risk score to each monitor data point when compared to a reference value. The SEG allows the clinical accuracy of a BG monitor to be portrayed in many ways, including as the percentages of data points falling into custom-defined risk zones. For modeled data the SEG, compared with the CEG and PEG, allows greater precision for quantifying risk, especially when the risks are low. This tool will be useful to allow regulators and manufacturers to monitor and evaluate glucose monitor performance in their surveillance programs.

American Association Of Clinical Endocrinologists And American College Of Endocrinology 2016 Outpatient Glucose Monitoring Consensus Statement

“…It incorporated the opinions of a greater number of expert clinicians (138). More recently, in 2014, a surveillance error grid with finer gradations in the categories for clinical error was introduced (139,140).…”

Assessing Sensor Accuracy for Non-Adjunct Use of Continuous Glucose Monitoring

“…In particular, the clinical interpretation of sensor errors and outliers would benefit from the recently introduced Surveillance Error-Grid, which was exclusively designed to gauge the clinical impact of SMBG errors, but could be adapted to evaluation of CGM error patterns. 60,61 In conclusion, CGM errors, time lag, and transient loss of sensitivity are primary obstacles to the adoption of this technology as a replacement to ''fingerstick'' self-monitoring. The thesis of this article is that CGM data contain rich information about a person's glycemic state and can help improve glycemic control if the information is processed appropriately.…”

Improving the Glucose Meter Error Grid With the Taguchi Loss Function

“…[1][2][3] Error grids are based on clinician opinion of potential outcomes, account for 100% of the data, and distinguish between no harm and various amounts of potential harm to patients based on the difference between a candidate glucose meter and reference. Error grid results are expressed graphically and as a tabulation of the percentage of results in each zone.…”