System Accuracy Evaluation of Four Systems for Self-Monitoring of Blood Glucose Following ISO 15197 Using a Glucose Oxidase and a Hexokinase-Based Comparison Method

Abstract

Background: The standard ISO (International Organization for Standardization) 15197 is widely accepted for the accuracy evaluation of systems for self-monitoring of blood glucose (SMBG). Accuracy evaluation was performed for 4 SMBG systems (Accu-Chek Aviva, ContourXT, GlucoCheck XL, GlucoMen LX PLUS) with 3 test strip lots each. To investigate a possible impact of the comparison method on system accuracy data, 2 different established methods were used.

Methods: The evaluation was performed in a standardized manner following test procedures described in ISO 15197:2003 (section 7.3). System accuracy was assessed by applying ISO 15197:2003 and in addition ISO 15197:2013 criteria (section 6.3.3). For each system, comparison measurements were performed with a glucose oxidase (YSI 2300 STAT Plus glucose analyzer) and a hexokinase (cobas c111) method.

Results: All 4 systems fulfilled the accuracy requirements of ISO 15197:2003 with the tested lots. More stringent accuracy criteria of ISO 15197:2013 were fulfilled by 3 systems (Accu-Chek Aviva, ContourXT, GlucoMen LX PLUS) when compared to the manufacturer's comparison method and by 2 systems (Accu-Chek Aviva, ContourXT) when compared to the alternative comparison method. All systems showed lot-to-lot variability to a certain degree; 2 systems (Accu-Chek Aviva, ContourXT), however, showed only minimal differences in relative bias between the 3 evaluated lots.

Conclusions: In this study, all 4 systems complied with the evaluated test strip lots with accuracy criteria of ISO 15197:2003. Applying ISO 15197:2013 accuracy limits, differences in the accuracy of the tested systems were observed, also demonstrating that the applied comparison method/system and the lot-to-lot variability can have a decisive influence on accuracy data obtained for a SMBG system.

Keywords: ISO 15197:2003; ISO 15197:2013; comparison measurement method; glucose oxidase method; hexokinase method; self-monitoring of blood glucose; system accuracy.

Conflict of interest statement

Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: All authors are employees of the IDT, which carries out studies on the evaluation of BG meters and medical devices for diabetes therapy on behalf of various companies. GF is general manager of the IDT. GF/IDT have received speakers’ honoraria or consulting fees from Abbott, Bayer, Berlin-Chemie, Becton-Dickinson, Dexcom, Menarini Diagnostics, Novo Nordisk, Roche Diagnostics, Sanofi, and Ypsomed.

© 2015 Diabetes Technology Society.

Figures

Figure 1.

Difference plots of 4 SMBG systems with 3 test strip lots each. Left-hand side: the glucose oxidase method was used for comparison measurements. Right-hand side: the hexokinase method was used for comparison measurements. Black lines: Criteria for system accuracy following ISO 15197:2003. Dashed lines: Criteria for system accuracy following ISO 15197:2013. For lot 3 of System C, 1 data point is not shown because the difference exceeds the y-axis scale (comparison measurement result: 155.5 mg/dl (glucose oxidase) and 164.6 mg/dl (hexokinase), system measurement result: 314 mg/dl).

Figure 2.

Relative bias according to Bland and Altman for each test strip lot. The relative bias evaluated by using the glucose oxidase (GOD) method is shown in blue diamonds with the upper 95% limit of agreement, the bias evaluated by using the hexokinase (HK) method is shown in red triangles with the lower 95% limits of agreement.