Stefan Pleus, Germany
Institut für Diabetes-Technologie, Forschungs- und Entwicklungsgesellschaft mbH an der Universität UlmPresenter of 2 Presentations
NON-INVASIVE GLUCOSE MONITORING BY A RAMAN SPECTROSCOPY-BASED PROTOTYPE AFTER MEAL CHALLENGE IN TYPE 1 DIABETES
Abstract
Background and Aims
One of the most promising technologies for non-invasive glucose monitoring (NIGM) in diabetes is Raman spectroscopy. We assessed the performance of a novel prototype in comparison with standard capillary blood glucose monitoring (BGM) and intermittent scanning continuous glucose monitoring (iscCGM).
Methods
In total, 15 subjects with type 1 diabetes underwent a carbohydrate-rich meal challenge during which BGM, iscCGM and NIGM measurements were performed for 450 min.
Results
Mean glucose values for the 3 monitoring systems are shown in the figure exhibiting a good match. The closeness of agreement generally improved with lower rates of change. During the initial 60 min after the standardized meal, the rates of change were: BGM, 2.0 ± 1.7 mg/dl/min, iscCGM, 1.5 ± 1.2 mg/dl/min, and NIGM, 0.8 ± 1.5 mg/dl/min (mean ± standard deviation).
Conclusions
In this proof-of-concept study, average glucose readings using NIGM showed good agreement with mean BGM and iscCGM data. The agreement improved with lower rates of change, indicating an effect of varying signal delay between the methods.
IMPACT OF TWO DIFFERENT COMPARISON METHODS ON APPARENT SYSTEM ACCURACY OF 18 CE-MARKED CURRENT-GENERATION SELF-MONITORING BLOOD GLUCOSE SYSTEMS
Abstract
Background and Aims
Systems for self-monitoring of blood glucose (SMBG) have to be sufficiently accurate for effective glycemic control. In accuracy studies, the selected comparison method can influence the apparent level of measurement accuracy. This study aimed at assessing the impact of two different comparison methods on the apparent accuracy of 18 CE-marked current-generation SMBG systems.
Methods
Measurement accuracy was assessed in a setting based on ISO 15197:2013 and additional analyses were performed, including minimal deviation within which 95% of results were found, relative bias, and mean absolute relative difference (MARD). Comparison measurements were performed on a glucose oxidase-based (GOD) and a hexokinase-based (HK) method in parallel.
Results
While ≈80% of SMBG systems met the accuracy criteria of ISO 15197 (i.e., ≥95% of results found within ±15 mg/dl or ±15% of comparison method results) when compared to the manufacturers reference method, only ≈67% did so independently from the applied comparison method. The minimal deviation within which 95% of results were found ranged from 7.7 to 19.7 mg/dl or % (GOD-based method) and from 5.3 to 20.1 mg/dl or % (HK-based method). The mean relative bias ranged from -6.6% to +5.7% (GOD-based method) and from -11.1% to +1.3% (HK-based method), whereas MARD results ranged from 3.7% to 9.8% and from 2.3% to 10.5%, respectively.
Conclusions
The results of this study indicate that the selected comparison measurement method may have an appreciable impact on SMBG systems’ apparent level of accuracy. Therefore, further steps towards harmonization of comparison method results are important.