scholarly journals Feasibility Evaluation of Metamaterial Microwave Sensors for Non-Invasive Blood Glucose Monitoring

Sensors ◽  
2021 ◽  
Vol 21 (20) ◽  
pp. 6871
Author(s):  
Lukas Malena ◽  
Ondrej Fiser ◽  
Paul R. Stauffer ◽  
Tomas Drizdal ◽  
Jan Vrba ◽  
...  
Keyword(s):  
Blood Glucose ◽  
Glucose Concentration ◽  
Blood Glucose Concentration ◽  
Numerical Models ◽  
Glucose Monitoring ◽  
Blood Glucose Monitoring ◽  
Maximum Relative Error ◽  
Non Invasive ◽  
Unit Cells ◽  
Higher Sensitivity

The use of microwave technology is currently under investigation for non-invasive estimation of glycemia in patients with diabetes. Due to their construction, metamaterial (MTM)-based sensors have the potential to provide higher sensitivity of the phase shift of the S21 parameter (∠S21) to changes in glucose concentration compared to standard microstrip transmission line (MSTL)-based sensors. In this study, a MSTL sensor and three MTM sensors with 5, 7, and 9 MTM unit cells are exposed to liquid phantoms with different dielectric properties mimicking a change in blood glucose concentration from 0 to 14 mmol/L. Numerical models were created for the individual experiments, and the calculated S-parameters show good agreement with experimental results, expressed by the maximum relative error of 8.89% and 0.96% at a frequency of 1.99 GHz for MSTL and MTM sensor with nine unit cells, respectively. MTM sensors with an increasing number of cells show higher sensitivity of 0.62° per mmol/L and unit cell to blood glucose concentration as measured by changes in ∠S21. In accordance with the numerical simulations, the MTM sensor with nine unit cells showed the highest sensitivity of the sensors proposed by us, with an average of 3.66° per mmol/L at a frequency of 1.99 GHz, compared to only 0.48° per mmol/L for the MSTL sensor. The multi-cell MTM sensor has the potential to proceed with evaluation of human blood samples.

Accuracy and precision assessment of a new blood glucose monitoring system

2016 ◽  
Vol 54 (1) ◽  
Author(s):  
Li-Nong Ji ◽  
Li-Xin Guo ◽  
Li-Bin Liu
Keyword(s):  
Blood Glucose ◽  
Glucose Concentration ◽  
Blood Glucose Concentration ◽  
Venous Blood ◽  
Glucose Monitoring ◽  
Blood Glucose Monitoring ◽  
Blood Samples ◽  
Glucose Testing ◽  
Blood Tests ◽  
Accuracy And Precision

AbstractBlood glucose self-monitoring by individuals with diabetes is essential in controlling blood glucose levels. The International Organization for Standardization (ISO) introduced new standards for blood glucose monitoring systems (BGMS) in 2013 (ISO 15197: 2013). The CONTOUR PLUSThis study evaluated the accuracy and precision of CONTOUR PLUS BGMS in quantitative glucose testing of capillary and venous whole blood samples obtained from 363 patients at three different hospitals.Results of fingertip and venous blood glucose measurements by the CONTOUR PLUS system were compared with laboratory reference values to determine accuracy. Accuracy was 98.1% (96.06%–99.22%) for fingertip blood tests and 98.1% (96.02%–99.21%) for venous blood tests. Precision was evaluated across a wide range of blood glucose values (5.1–17.2 mmol/L), testing three blood samples repeatedly 15 times with the CONTOUR PLUS blood glucose meter using test strips from three lots. All within-lot results met ISO criteria (i.e., SD<0.42 mmol/L for blood glucose concentration <5.55 mmol/L; CV<7.5% for blood glucose concentration ≥5.55 mmol/L). Between-lot variations were 1.5% for low blood glucose concentration, 2.4% for normal and 3.4% for high.Accuracy of both fingertip and venous blood glucose measurements by the CONTOUR PLUS system was >95%, confirming that the system meets ISO 15197: 2013 requirements.

Dispositivo de Monitoreo de Glucosa en Sangre No Invasivo mediante Infrarrojo Cercano

2021 ◽  
Author(s):  
◽  
G. Silos Chincoya
Keyword(s):  
Blood Glucose ◽  
Glucose Concentration ◽  
Near Infrared ◽  
Blood Glucose Concentration ◽  
Glucose Monitoring ◽  
Blood Glucose Monitoring ◽  
Signal Acquisition ◽  
Infrared Transmission ◽  
Glucose Levels ◽  
Concentration Levels

This researching study aims to report the development of a prototype device that may provide the estimation of the blood glucose concentration levels non-invasively using near-infrared transmission spectroscopy techniques. The system works in three stages: signal acquisition, calibration, and estimation of blood glucose concentration levels. The acquisition of the signal used an optical sensor based on a transimpedance circuit to obtain the different intensity changes of the emitting source in terms of voltage. The calibration of the proposed device was carried out taking as reference, the values of a commercial device that performs invasive blood glucose monitoring, with the aim of obtaining greater precision. In the last stage, the Lambert-Beer Law is mainly used to estimate glucose concentration. The proposed device presents a relationship between optical signals and variations in blood glucose levels with an accuracy of 90% in average which is statistically representative considering the class of non-invasive technology used for developing the proposed device.

Indole as a new tentative marker in exhaled breath for non-invasive blood glucose monitoring of diabetic subjects

2021 ◽  
Author(s):  
Herbert Fink ◽  
Tim Maihöfer ◽  
Jeffrey Bender ◽  
Jochen Schulat
Keyword(s):  
Blood Glucose ◽  
Diabetes Management ◽  
Glucose Monitoring ◽  
Blood Glucose Monitoring ◽  
Glucose Measurement ◽  
Diabetic Patients ◽  
Exhaled Breath ◽  
Invasive Approach ◽  
Test Strips ◽  
Non Invasive

Abstract Blood glucose monitoring (BGM) is the most important part of diabetes management. In classical BGM, glucose measurement by test strips involves invasive finger pricking. We present results of a clinical study that focused on a non-invasive approach based on volatile organic compounds (VOCs) in exhaled breath. Main objective was the discovery of markers for prediction of blood glucose levels (BGL) in diabetic patients. Exhaled breath was measured repeatedly in 60 diabetic patients (30 type 1, 30 type 2) in fasting state and after a standardized meal. Proton Transfer Reaction Time of Flight Mass Spectrometry (PTR-ToF-MS) was used to sample breath every 15 minutes for a total of six hours. BGLs were tested in parallel via BGM test strips. VOC signals were plotted against glucose trends for each subject to identify correlations. Exhaled indole (a bacterial metabolite of tryptophan) showed significant mean correlation to BGL (with negative trend) and significant individual correlation in 36 patients. The type of diabetes did not affect this result. Additional experiments of one healthy male subject by ingestion of lactulose and 13C-labeled glucose (n=3) revealed that exhaled indole does not directly originate from food digestion by intestinal microbiota. As indole has been linked to human glucose metabolism, it might be a tentative marker in breath for non-invasive BGM. Clinical studies with greater diversity are required for confirmation of such results and further investigation of metabolic pathways.

Non-Invasive Blood Glucose Monitoring by Means of near Infrared Spectroscopy: Methods for Improving the Reliability of the Calibration Models

1997 ◽  
Vol 20 (5) ◽  
pp. 285-290 ◽  
Author(s):  
U.A. Müller ◽  
B. Mertes ◽  
C. Fischbacher ◽  
K.U. Jageman ◽  
K. Danzer
Keyword(s):  
Blood Glucose ◽  
Near Infrared ◽  
Glucose Monitoring ◽  
Blood Glucose Monitoring ◽  
Least Squares Regression ◽  
Non Invasive ◽  
Infrared Reflection ◽  
Calibration Models ◽  
Infrared Reflection Spectroscopy

The feasibility of using near infrared reflection spectroscopy for non-invasive blood glucose monitoring is discussed. Spectra were obtained using a diode-array spectrometer with a fiberoptic measuring head with a wavelength ranging from 800 nm to 1350 nm. Calibration was performed using partial least-squares regression and radial basis function networks. The results of different methods used to evaluate the quality of the recorded spectra in order to improve the reliability of the calibration models, are presented.

scholarly journals A Review of Non-Invasive Optical Systems for Continuous Blood Glucose Monitoring

Sensors ◽  
2021 ◽  
Vol 21 (20) ◽  
pp. 6820
Author(s):  
Bushra Alsunaidi ◽  
Murad Althobaiti ◽  
Mahbubunnabi Tamal ◽  
Waleed Albaker ◽  
Ibraheem Al-Naib
Keyword(s):  
Blood Glucose ◽  
Glucose Monitoring ◽  
Daily Basis ◽  
Glucose Sensing ◽  
Blood Glucose Monitoring ◽  
Optical Systems ◽  
Glucose Levels ◽  
Non Invasive ◽  
Blood Glucose Levels ◽  
Continuous Blood Glucose Monitoring

The prevalence of diabetes is increasing globally. More than 690 million cases of diabetes are expected worldwide by 2045. Continuous blood glucose monitoring is essential to control the disease and avoid long-term complications. Diabetics suffer on a daily basis with the traditional glucose monitors currently in use, which are invasive, painful, and cost-intensive. Therefore, the demand for non-invasive, painless, economical, and reliable approaches to monitor glucose levels is increasing. Since the last decades, many glucose sensing technologies have been developed. Researchers and scientists have been working on the enhancement of these technologies to achieve better results. This paper provides an updated review of some of the pioneering non-invasive optical techniques for monitoring blood glucose levels that have been proposed in the last six years, including a summary of state-of-the-art error analysis and validation techniques.

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