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Link M.,Institute For Diabetes Technology Forschungs Und Entwicklungsgesellschaft Mbh | Schmid C.,Institute For Diabetes Technology Forschungs Und Entwicklungsgesellschaft Mbh | Pleus S.,Institute For Diabetes Technology Forschungs Und Entwicklungsgesellschaft Mbh | Baumstark A.,Institute For Diabetes Technology Forschungs Und Entwicklungsgesellschaft Mbh | And 3 more authors.
Journal of diabetes science and technology | Year: 2015

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. © 2015 Diabetes Technology Society.


Patte C.,Hoffmann-La Roche | Pleus S.,Institute For Diabetes Technology Forschungs Und Entwicklungsgesellschaft Mbh | Galley P.,Hoffmann-La Roche | Weinert S.,Hoffmann-La Roche | And 2 more authors.
Journal of Diabetes Science and Technology | Year: 2012

Introduction: Safe and effective closed-loop control (artificial pancreas) is the ultimate goal of insulin delivery. In this study, we examined the performance of a closed-loop control algorithm used for the overnight time period to safely achieve a narrow target range of blood glucose (BG) concentrations prior to breakfast. The primary goal was to compare the quality of algorithm control during repeated overnight experiments. Materials and Methods: Twenty-three subjects with type 1 diabetes performed 2 overnight experiments on each of three visits at the study site, resulting in 138 overnight experiments. On the first evening, the subject's insulin therapy was applied; on the second, the insulin was delivered by an algorithm based on subcutaneous continuous glucose measurements (including meal control) until midnight. Overnight closed-loop control was applied between midnight and 6 a.m. based on hourly venous BG measurements during the first and second nights. Results: The number of BG values within the target range (90-150 mg/dl) increased from 52.9% (219 out of 414 measurements) during the first nights to 72.2% (299 out of 414 measurements) during the second nights (p < .001, χ2-test). The occurrence of hypoglycemia interventions was reduced from 14 oral glucose interventions, the latest occurring at 2:36 a.m. during the first nights, to 1 intervention occurring at 1:02 a.m. during the second nights (p < .001, χ2-test). Conclusions: Overnight controller performance improved when optimized initial control was given; this was suggested by the better metabolic control during the second night. Adequate controller run-in time seems to be important for achieving good overnight control. In addition, the findings demonstrate that hourly BG data are sufficient for the closed-loop control algorithm tested to achieve appropriate glycemic control. © Diabetes Technology Society.


PubMed | Profil Institute fur Stoffwechselforschung GmbH, Edingen Neckarhausen and Institute For Diabetes Technology Forschungs Und Entwicklungsgesellschaft Mbh
Type: Journal Article | Journal: Journal of diabetes science and technology | Year: 2015

In the European Union (EU), the ISO (International Organization for Standardization) 15197 standard is applicable for the evaluation of systems for self-monitoring of blood glucose (SMBG) before the market approval. In 2013, a revised version of this standard was published. Relevant revisions in the analytical performance requirements are the inclusion of the evaluation of influence quantities, for example, hematocrit, and some changes in the testing procedures for measurement precision and system accuracy evaluation, for example, number of test strip lots. Regarding system accuracy evaluation, the most important change is the inclusion of more stringent accuracy criteria. In 2014, the Food and Drug Administration (FDA) in the United States published their own guidance document for the premarket evaluation of SMBG systems with even more stringent system accuracy criteria than stipulated by ISO 15197:2013. The establishment of strict accuracy criteria applicable for the premarket evaluation is a possible approach to further improve the measurement quality of SMBG systems. However, the system accuracy testing procedure is quite complex, and some critical aspects, for example, systematic measurement difference between the reference measurement procedure and a higher-order procedure, may potentially limit the apparent accuracy of a given system. Therefore, the implementation of a harmonized reference measurement procedure for which traceability to standards of higher order is verified through an unbroken, documented chain of calibrations is desirable. In addition, the establishment of regular and standardized post-marketing evaluations of distributed test strip lots should be considered as an approach toward an improved measurement quality of available SMBG systems.


Freckmann G.,Institute For Diabetes Technology Forschungs Und Entwicklungsgesellschaft Mbh | Link M.,Institute For Diabetes Technology Forschungs Und Entwicklungsgesellschaft Mbh | Schmid C.,Institute For Diabetes Technology Forschungs Und Entwicklungsgesellschaft Mbh | Pleus S.,Institute For Diabetes Technology Forschungs Und Entwicklungsgesellschaft Mbh | And 2 more authors.
Diabetes Technology and Therapeutics | Year: 2015

Background: Adherence to established standards (e.g., International Organization for Standardization [ISO] 15197) is important to ensure comparable and sufficient accuracy of systems for self-monitoring of blood glucose (SMBG). Accuracy evaluation was performed for different SMBG systems available in Europe with three reagent lots each. Materials and Methods: Test procedures followed the recently published revision ISO 15197:2013. Comparison measurements were performed with a glucose oxidase (YSI 2300 STAT Plus™ glucose analyzer; YSI Inc., Yellow Springs, OH) and a hexokinase (cobas Integra® 400 Plus analyzer; Roche Instrument Center, Rotkreuz, Switzerland) method. Compliance with ISO 15197:2013 accuracy criteria was determined by calculating the percentage of results within ±15% or within ±0.83 mmol/L of the comparison measurement results for glucose concentrations at and above or below 5.55 mmol/L, respectively, and by calculating the percentage of results within consensus error grid Zones A and B. Results: Seven systems showed with all three tested lots that 95-100% of the results were within the accuracy limits of ISO 15197:2013 and that 100% of results were within consensus error grid Zones A and B, irrespective of the comparison method used. Regarding results of individual lots, slight differences between the glucose oxidase method and the hexokinase method were found. Accuracy criteria of ISO 15197:2003 (±20% for concentrations ≥4.2 mmol/L and±0.83 mmol/L for concentrations <4.2 mmol/L) were fulfilled by eight systems with all three lots and by one system with two lots. Conclusions: In this study, seven systems complied with the accuracy criteria of ISO 15197:2013. The results also indicate that the comparison measurement method/system is important, as it may have a considerable impact on accuracy data obtained for a system. Copyright 2015, Mary Ann Liebert, Inc.


Freckmann G.,Institute For Diabetes Technology Forschungs Und Entwicklungsgesellschaft Mbh | Schmid C.,Institute For Diabetes Technology Forschungs Und Entwicklungsgesellschaft Mbh | Baumstark A.,Institute For Diabetes Technology Forschungs Und Entwicklungsgesellschaft Mbh | Pleus S.,Institute For Diabetes Technology Forschungs Und Entwicklungsgesellschaft Mbh | And 2 more authors.
Journal of Diabetes Science and Technology | Year: 2012

Background: The accuracy of systems for self-monitoring of blood glucose is important, as reliable measurement results are a prerequisite for therapeutic decisions. Methods: This system accuracy evaluation study was performed according to DIN EN ISO 15197:2003 for 43 Conformité Européenne (CE)-labeled blood glucose (BG) monitoring systems. Measurement results of each system were compared with results of the designated comparison method (manufacturer's measurement procedure): glucose oxidase method (YSI 2300 glucose analyzer) or hexokinase method (Hitachi 917/ cobas 501). Results: Complete assessment according to the International Organization for Standardization (ISO) standard was performed for 34 out of 43 systems, and 27 (79.4%) meet the requirements of the standard, i.e., ≥95% of their results showed at least the minimum acceptable accuracy. For 9 of the 43 systems, complete accuracy assessment was not performed due to an oxygen sensitivity (manufacturer's labeling). The bias (according to Bland and Altman) of all 43 evaluated systems ranged from -14.1% to +12.4%. Conclusions: From the 34 systems completely assessed, 7 systems did not fulfill the minimal accuracy requirements of the ISO standard. The CE mark apparently does not guarantee that all BG systems provide accuracy according to the standard. Because inaccurate systems bear the risk of false therapeutic decisions, regular and standardized evaluation of BG meters and test strips should be requested in order to ensure adherence to quality standards. © Diabetes Technology Society.


PubMed | Institute For Diabetes Technology Forschungs Und Entwicklungsgesellschaft Mbh
Type: Comparative Study | Journal: Diabetes technology & therapeutics | Year: 2015

Adherence to established standards (e.g., International Organization for Standardization [ISO] 15197) is important to ensure comparable and sufficient accuracy of systems for self-monitoring of blood glucose (SMBG). Accuracy evaluation was performed for different SMBG systems available in Europe with three reagent lots each.Test procedures followed the recently published revision ISO 15197:2013. Comparison measurements were performed with a glucose oxidase (YSI 2300 STAT Plus glucose analyzer; YSI Inc., Yellow Springs, OH) and a hexokinase (cobas Integra() 400 Plus analyzer; Roche Instrument Center, Rotkreuz, Switzerland) method. Compliance with ISO 15197:2013 accuracy criteria was determined by calculating the percentage of results within 15% or within 0.83mmol/L of the comparison measurement results for glucose concentrations at and above or below 5.55mmol/L, respectively, and by calculating the percentage of results within consensus error grid Zones A and B.Seven systems showed with all three tested lots that 95-100% of the results were within the accuracy limits of ISO 15197:2013 and that 100% of results were within consensus error grid Zones A and B, irrespective of the comparison method used. Regarding results of individual lots, slight differences between the glucose oxidase method and the hexokinase method were found. Accuracy criteria of ISO 15197:2003 (20% for concentrations 4.2mmol/L and0.83mmol/L for concentrations <4.2mmol/L) were fulfilled by eight systems with all three lots and by one system with two lots.In this study, seven systems complied with the accuracy criteria of ISO 15197:2013. The results also indicate that the comparison measurement method/system is important, as it may have a considerable impact on accuracy data obtained for a system.


PubMed | Institute For Diabetes Technology Forschungs Und Entwicklungsgesellschaft Mbh
Type: Clinical Trial | Journal: Journal of diabetes science and technology | Year: 2013

The performance of a continuous glucose monitoring (CGM) system in the early stage of development was assessed in an inpatient setting that simulates daily life conditions of people with diabetes. Performance was evaluated at low glycemic, euglycemic, and high glycemic ranges as well as during phases with rapid glucose excursions.Each of the 30 participants with type 1 diabetes (15 female, age 47 12 years, hemoglobin A1c 7.7% 1.3%) wore two sensors of the prototype system in parallel for 7 days. Capillary blood samples were measured at least 16 times per day (at least 15 times per daytime and at least once per night). On two subsequent study days, glucose excursions were induced. For performance evaluation, the mean absolute relative difference (MARD) between CGM readings and paired capillary blood glucose readings and precision absolute relative difference (PARD), i.e., differences between paired CGM readings were calculated.Overall aggregated MARD was 9.2% and overall aggregated PARD was 7.5%. During induced glucose excursions, MARD was 10.9% and PARD was 7.8%. Lowest MARD (8.5%) and lowest PARD (6.4%) were observed in the high glycemic range (euglycemic range, MARD 9.1% and PARD 7.4%; low glycemic range, MARD 12.3% and PARD 12.4%).The performance of this prototype CGM system was, particularly in the hypoglycemic range and during phases with rapid glucose fluctuations, better than performance data reported for other commercially available systems. In addition, performance of this prototype sensor was noticeably constant over the whole study period. This prototype system is not yet approved, and performance of this CGM system needs to be further assessed in clinical studies.


PubMed | Institute For Diabetes Technology Forschungs Und Entwicklungsgesellschaft Mbh
Type: Evaluation Studies | Journal: Journal of diabetes science and technology | Year: 2015

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.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.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 manufacturers 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.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.


PubMed | Institute For Diabetes Technology Forschungs Und Entwicklungsgesellschaft Mbh
Type: Editorial | Journal: Journal of diabetes science and technology | Year: 2015

It remains to be seen as to what share of the market FGM will achieve if the manufacturer can supply any amount desired.Will a significant portion of the glucose monitoring market then be taken over by FGM? The availability of FGM as anew option for glucose monitoring can basically be evaluated positively and it does indeed clearly show the benefit ofmore information on the glucose trend. The relatively low price for glucose monitoring using FGM and the unusual market introduction (not first via the National Association of Statutory Health Insurance Funds, as was the case with CGM) have given increased attention to the use of more glucose information. It will likely take a certain amount of time before other providers are able to bring different FGM systems to the market.The option of coupling a CGM system with an insulin pump offers the perspective of an automated insulin application,that is, a closed-loop system. Such systems are currently being tested under everyday conditions, although it is not possible to predict when they will actually reach the market.There are, however, such couplings where algorithms are responsible for shutting off insulin delivery when the glucose concentration reaches a defined level or if it will be reached in the foreseeable future. This significantly helps prevent hypoglycemia. These options are only available with CGM. The aim of this commentary is to present the differences between CGM and FGM, including the advantages and disadvantages of both approaches. We see significant benefits in both options based on the different positioning of the approaches and the different user groups.

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