Measurement Of Glucose Concentration Research Articles

Optimization of Optical Biosensor Based on 1D Photonic Crystals with Metaheuristic Algorithms for Measuring Glucose Concentration

We aim to simulate an optimal optical biosensor based on one-dimensional crystal photonics, for measuring blood and urine glucose concentration. By optimizing the sensor structure through metaheuristic optimization algorithms, sensitivity was increased. To measure blood and urine glucose concentration, these materials are used as a defect layer in one-dimensional crystal photonics, consisting of three materials: magnesium fluoride (MgF2), borosilicate glass (BK7), and orphan iodide (LiI) with refractive indices of 37/1, 1/5, and 1/99. By changing the concentration of glucose, the refractive index of the defect layer changes, changing the optical properties of the defect layer in the photonic crystal and the spectrum of transmitted and reflected light. According to the amount of light absorption by glucose, a wavelength range of 900–2200 nm (near infrared) was used as the input light. The transfer matrix method was used to calculate multi-layer systems. This method is based on the definition of two matrices, the boundary matrix and the diffusion matrix, which can be used to directly apply the boundary conditions. By plotting the spectrum passing through the crystal using the transfer matrix method and determining the location of the peak in the spectrum, the sensitivity of the sensor was calculated for different concentrations of glucose in blood and urine. The sensitivity obtained before optimization was 530 nm RIU−1, while after optimization it reached 842 nm RIU−1.

Urine glucose concentration detection biosensor using one-dimensional photonic crystals with periodical and Fibonacci sequences based on Tamm plasmon resonance

This paper presents the design of biosensors utilizing one-dimensional photonic crystals with periodical and Fibonacci sequences for measuring glucose concentration in urine, aimed at facilitating continuous blood glucose monitoring for diabetic patients. Exploiting Tamm plasmon resonance within a photonic band gap in the medium wave infrared band, the biosensor comprises a configuration with a one-dimensional photonic crystal and an Ag layer deposited on an infrared prism, with a urine sample layer in between. Utilizing the transfer matrix method, the reflection spectra for electromagnetic waves are calculated. The wavelength position of the Tamm plasmon resonant dip is influenced by variations in glucose concentration within the urine sample. This is attributed to the distinct refractive indices exhibited by urine samples with different glucose concentrations. Optimizing biosensor performance under various incident angles involves adjusting the Ag layer and urine sample thicknesses while maintaining excellent linear characteristics. The optimal performance of the biosensor with Fibonacci sequence one-dimensional photonic crystal is significantly superior, with a sensitivity of 113,000 nm RIU−1, a figure of merit of 2.05 × 105 RIU−1, and a detection limit of 4.84 × 10−7 RIU. The combination of high performance and a straightforward structure makes the proposed biosensors for detecting urine glucose concentrations promising in biomedical diagnostics.

Metamaterial Microwave Sensor for Glucose Level Measurement Based on Strip Line with Complementary Split Ring Resonator

This research focuses on investigating glucose meters utilizing metamaterial microwave sensors. The metamaterial microwave sensor is designed with a strip line loaded with a complementary split ring. The sensor is designed to conduct Ansys high‐frequency structure simulator and uses conductor material coated on a hydrocarbon ceramic laminate (Roger RO4232) substrate, with a sweep frequency range of 1–6 GHz. The signal of the metamaterial microwave sensor depends on the change in glucose permittivity and conductivity when the glucose concentration changes. The research involves designing a simulation model to explore the impact of complementary split ring size on the sensor's response to changes in glucose permittivity. Additionally, experiments are conducted using the proposed sensor to measure glucose concentration in solution, aiming to analyze trends in sensor response to varying concentrations of glucose and evaluate its sensitivity to changes in glucose concentration. The experimental results indicate that the metamaterial microwave sensor is able to respond to variations in glucose level, a sensitivity of the proposed sensor is 0.0345 dB (mg dL−1)−1 in range of 0–110 mg dL−1 with R2 0.9628.

Harnessing Redox Polymer Dynamics for Enhanced Glucose-Oxygen Coupling in Dual Biosensing and Therapeutic Applications.

The burgeoning field of continuous glucose monitoring (CGM) for diabetes management faces significant challenges, particularly in achieving precise and stable biosensor performance under changing environmental conditions such as varying glucose concentrations and O2 levels. To address this, we present a novel biosensor based on the electroless coupling of glucose oxidation catalyzed by flavin-dependent glucose dehydrogenase (FAD-GDH) and O2 reduction catalyzed by bilirubin oxidase (BOD) via a redox polymer, dimethylferrocene-modified linear poly(ethylenimine), FcMe2-LPEI. Initial cyclic voltammetry tests confirm the colocalization of both enzymatic reactions within the potential range of the polymer, indicating an effective electron shuttle mechanism. As a result, we created a hybrid biosensor that operates at open-circuit potential (OCP). It can detect glucose concentrations of up to 100 mM under various O2 conditions, including ambient air. This resulted from optimizing the enzyme ratio to 120 ± 10 mUBOD·UFAD-GDH-1·atmO2-1. This biosensor is highly sensitive, a crucial feature for CGM applications. This distinguishes it from FAD-GDH traditional biosensors, which require a potential to be applied to measure glucose concentrations up to 30 mM. In addition, this biosensor demonstrates the ability to function as a noninvasive, external device that can adapt to changing glucose levels, paving the way for its use in diabetes care and, potentially, personalized healthcare devices. Furthermore, by leveraging the altered metabolic pathways in tumor cells, this system architecture opened up new avenues for targeted glucose scavenging and O2 reduction in cancer therapy.

Non-Enzymatic Glucose Sensors Composed of Polyaniline Nanofibers with High Electrochemical Performance.

The measurement of glucose concentration is a fundamental daily care for diabetes patients, and therefore, its detection with accuracy is of prime importance in the field of health care. In this study, the fabrication of an electrochemical sensor for glucose sensing was successfully designed. The electrode material was fabricated using polyaniline and systematically characterized using scanning electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and UV-visible spectroscopy. The polyaniline nanofiber-modified electrode showed excellent detection ability for glucose with a linear range of 10 μM to 1 mM and a detection limit of 10.6 μM. The stability of the same electrode was tested for 7 days. The electrode shows high sensitivity for glucose detection in the presence of interferences. The polyaniline-modified electrode does not affect the presence of interferences and has a low detection limit. It is also cost-effective and does not require complex sample preparation steps. This makes it a potential tool for glucose detection in pharmacy and medical diagnostics.

Wearable, disposable and non-enzymatic fluorescence nanosensor for monitoring sweat glucose through smartphone

The promise of non-invasive health monitoring has fuelled the development of wearable biosensors for in situ detection of biological analytes in sweat. This paper presents a new fluorescent nanosensor probe based on boric acid functionalized and heteroatom doped carbon quantum dots (CQDs) embedded in paper-based analytical devices and integrated with a hydrophilic cotton thread-based microfluidic channel for the development of a flexible, wearable, biocompatible, and biodegradable sweat sensor for real-time measurement of sweat glucose concentration via smartphone readout. The morphological, physiochemical, compositional, crystallinity, and optical properties of nanosensors were extensively investigated. CQD particle sizes were found to be widely dispersed, ranging from 2.6 to 7.1 nm, with an average diameter of 4.38 nm. A dual response via fluorescence and colorimetric change was demonstrated for on-site sweat glucose monitoring using a smartphone camera to capture images in RGB (red, green, and blue) format and analyse them simultaneously by a customized android app, with quantitative results displayed on the smartphone. The limit of detection value for in situ measurement of sweat glucose concentration was 1.40 to 2.00 μM (25.25 to 36.13 μg/dL) and the limit of quantification value was 4.67 to 6.69 μM (84.16–120.44 μg/dL) in the pH range of 4.5 to 7.5. The developed sensor's performance metrics were validated using a standard clinical technique, which indicates strong correlation between two methods with Pearson correlation coefficient values of 0.83 and 0.80 for non-diabetic and type- II diabetes patients, respectively. Besides, interference, spike, and recovery studies were carried out with recovery rates ranging from 96.5 to 105.8 %, demonstrating good repeatability and reproducibility. Furthermore, feasible fluorescence quenching processes have been explored. In addition, the disposable and biodegradable nature of the nanosensor probe was studied by throwing it into the soil in the natural environment, where it dissolves almost spontaneously after three weeks.

High concordance of blood glucose measurement in cats between a beta prototype glucometer device and a reference laboratory standard in a clinical setting.

The objective of this study was to evaluate the accuracy of a beta prototype version of a new portable blood glucose meter in feline patients. 60 client-owned cats. In this prospective study, 3-mL blood samples were collected from each cat and analyzed in triplicate using a beta prototype device (AlphaTRAK 3 [AT3]) and by a reference lab standard immediately after collection. Accuracy of the AT3 device was determined in accordance with the International Organization of Standardization (ISO) 15197:2013 criteria, including Bland-Altman plotting and consensus error grid analysis. A Passing-Bablok regression analysis was also performed. 96% of feline measurements fell within the ISO accuracy threshold, and 100% of measurements fell within zones A and B of the consensus error grid, meeting the ISO accuracy requirements. There was no significant bias in the data according to the Bland-Altman analysis. Within the full range of glucose concentrations (20 to 750 mg/dL) the correlation coefficient between the AT3 and the reference lab standard was 0.99. There was no significant constant or proportional bias present in the data. The AT3 device met the ISO requirements and is accurate for measurement of blood glucose concentrations in cats.

Non-invasive measurements of blood glucose levels by time-gating mid-infrared optoacoustic signals

Non-invasive glucose monitoring (NIGM) represents an attractive alternative to finger pricking for blood glucose assessment and management of diabetes. Nevertheless, current NIGM techniques do not measure glucose concentrations in blood but rely on indirect bulk measurement of glucose in interstitial fluid, where glucose is diluted and glucose dynamics are different from those in the blood, which impairs NIGM accuracy. Here we introduce a new biosensor, termed depth-gated mid-infrared optoacoustic sensor (DIROS), which allows, for the first time, non-invasive glucose detection in blood-rich volumes in the skin. DIROS minimizes interference caused by the stratum corneum and other superficial skin layers by time-gating mid-infrared optoacoustic signals to enable depth-selective localization of glucose readings in skin. In measurements on the ears of (female) mice, DIROS displays improved accuracy over bulk-tissue glucose measurements. Our work demonstrates how signal localization can improve NIGM accuracy and positions DIROS as a holistic approach, with high translational potential, that addresses a key limitation of current NIGM methods.

Ultra-sensitive fiber optic sensor for glucose concentration measurement based on Vernier effect in cascaded Mach–Zehnder interferometers

In this paper, a fiber optic glucose concentration sensor based on cascaded Mach–Zehnder interferometers (CMZIs) was proposed and experimentally verified. Two single-mode fibers (SMFs) with slightly different tapering lengths and as well free spectral ranges (FSRs) were obtained through the melt-drawn cones technique and then were cascaded together to achieve the Vernier effect (VE). Experimental results showed that the measurement sensitivity of glucose concentration based on a single tapered SMF was 0.0494 nm (mmol l−1)−1. Furthermore, the measurement sensitivity based on the cascaded tapered SMFs was enhanced by 4.86 times to an ultra-high level of 0.2402 nm (mmol l−l)−1. The resolution reached 0.083 mmol l−1. The refractive index sensitivity reached 9066 nm/RIU. The resolution reached 2.21 × 10−6 RIU. In addition, the proposed glucose concentration sensor based on CMZIs shows good hysteresis. In conclusion, the designed sensor, showing the merits of easy to fabricate, high sensitivity, and high detection resolution, could be used to monitor the tiny variation in glucose concentration.

Effects of Physalis peruviana L. (leaf crude extracts) on blood glucose and functional biomarkers in streptozotocin-nicotinamide-induced diabetic rats.

Promoting antidiabetic phytomedicines necessitates evidence-based preclinical investigations, particularly in animal models. The present study investigated the validity of using the streptozotocin-nicotinamide-induced type 2 diabetic (STZ/NA-induced T2DM) model to evaluate the effects of Physalis peruviana leaf crude extracts on controlling blood glucose levels and regulating physiological biomarkers in rats. Aqueous and methanol extracts dissolved in carboxymethylcellulose 1% (100, 200, mg/kg/day) were administered orally to STZ/NA-induced T2DM rats alongside glibenclamide (5 mg/kg) as the standard drug for four weeks. Blood samples were collected in fasting rats on days 1, 7, 14, 21, and 28 to measure glucose concentration, lipoprotein-cholesterol, and common serum biomarkers. Nutrition characteristics were also monitored, as well as the pancreas histology. Administration of STZ/NA in Wistar rats induced the T2DM significantly lower than did STZ alone (glycaemia 200 vs 400 mg/dL). The significant effects observed with plant extracts compared to untreated diabetic rats were blood glucose reduction (28-52 %), HDL-C increase, LDL-C decrease, ALAT increase, WBC increase, body weight gain (24%), and pancreas protection. The findings confirm the antidiabetic effect of P. peruviana in T2DM animal model.

Metabolic Effects of Brown Adipose Tissue Activity Due to Cold Exposure in Humans: A Systematic Review and Meta-Analysis of RCTs and Non-RCTs.

Brown adipose tissue (BAT), specialized in thermoregulation in mammals, has been linked to improved glucose and lipid homeostasis when activated by cold exposure (CE). This systematic review and meta-analysis assessed the metabolic effects of CE-induced BAT activation in healthy humans, examining changes in glucose and lipid metabolism compared to thermoneutrality (TN). A literature search was conducted, identifying relevant human studies, including randomized controlled trials (RCTs) and non-RCTs, based on predefined inclusion criteria. Seven studies (a total of 85 participants) fully met the criteria. Data on plasma glucose, insulin, triglycerides (TGs), and free fatty acids (FFAs) were extracted for meta-analysis. When comparing TN and CE under fasting conditions, there were no significant changes in glucose, insulin, or TG concentrations (all p > 0.36). In contrast, CE significantly increased FFA concentrations (p = 0.002; n = 38). Bias was absent for all parameters, but heterogeneity was observed for insulin (I2 = 74.8%). CE primarily affects FFA concentration, likely reflecting cold-induced BAT activity. This suggests that circulating FFAs, serving as the primary fuel for thermogenesis, could indicate BAT activation. However, understanding the effects of BAT activation on overall metabolism requires a broader approach beyond fasting glucose and lipid concentration measurements.

A Novel Biosensor for the Detection of Glucose Concentration Using the Dual-Peak Long Period Grating in the Near- to Mid-Infrared.

In this article, we demonstrate an improved efficient fibre sensor with a high sensitivity to measure glucose concentrations in the physiological range of human beings, operating in a broad spectral bandwidth from the near- to mid-infrared. The sensor consists of a dual-peak long period grating (DPLPG) with a period of 150 μm inscribed in an optical fibre with a diameter of 80 μm. The investigation of sensing for refractive index results in a sensitivity of ~-885.7 nm/refractive index unit (RIU) and ~2008.6 nm/RIU in the range of 1.30-1.44. The glucose measurement is achieved by the immobilisation of a layer of enzyme of glucose oxidase (GOD) onto the fibre surface for the selective enhancement of sensitivity for glucose. The sensor can measure glucose concentrations with a maximum sensitivity of -36.25 nm/(mg/mL) in the range of 0.1-3.0 mg/mL. To the best of our knowledge, this is the highest sensitivity ever achieved for a measurement of glucose with a long period grating-based sensor, indicating its potential for many applications including pharmaceutical, biomedical and food industries.

On Standardization and Evaluation of Continuous Glucose Monitoring Systems

Continuous glucose monitoring (CGM) systems are often used to monitor blood glucose levels. Most commercially available CGM systems continuously measure glucose concentrations in the interstitial fluid of subcutaneous adipose tissue. However, there is currently no internationally accepted reference method for measuring interstitial fluid glucose, which is a prerequisite for metrological traceability of glucose measurements obtained using CGM. Since manufacturers do not provide information about the traceability chain and measurement uncertainty of their systems, CGM-derived glucose values cannot currently be adequately traced to standards or higher order reference measurement procedures. Additionally, the «mean absolute relative difference» (MARD) often used to describe the analytical performance of CGM systems is dependent on many factors. For example, the MARD can be significantly affected by the «lag time» between the change in blood glucose and interstitial glucose, especially at high rates of change in glucose. Finally, modern automated insulin delivery (ADI) systems with integrated CGM can automatically suspend or increase insulin infusion in response to current and/or predicted hypoglycemic and hyperglycemic phenomenon in children and adults with type 1 diabetes mellitus (T1DM). The purpose of the review is justification of the necessity to establish metrological traceability of glucose measurements with CGM systems, as well as a discussion of the analytical and clinical characteristics of CGM systems proposed by various professional communities. Based on the results of the review, it was concluded that it is necessary to 1) develop metrological support for glucose measurements performed using CGM systems, 2) solve the problems of ensuring the accessibility and usability of CGM systems by patients in real conditions.

To Compare Blood Glucose Estimation Using the GOD-PAP Technique with the Hexokinase Method

Glucose is the major source of energy for all the processes working within the human body and hence it's the major carbohydrate required. During starvation or fasting, its concentration in blood is maintained by glycogenolysis and gluconeogenesis otherwise, a routine diet is sufficient for this task. Routine methods like glucose-oxidase coupled dehydrogenase are most commonly used on semiautomatic instruments with mono reagent. Hexokinase is the definite method to measure glucose concentration during different fed and fasting states but it requires an automated instrument and specific reagent which comparatively affects its cost. Objective: To compare the GOD-PAP and Hexokinase methods for blood glucose estimation. Methodology: This study was conducted in the Chemical pathology lab and Diabetic clinic of Sheikh Zayed Medical College and Hospital, Rahim Yar Khan from June to December 2023. 110 samples were obtained. Both genders with hyperglycemia and normoglycemia were selected. Hemolyzed, lipemic, icteric specimens and blood samples with low glucose <50 mg/dl were excluded. Results: 110 patient specimens were analyzed on both fully automated and semi-automatic instruments for method comparison. Precision determined by replication study in which Random Error was (RE) < Total Allowable Error (TAE). The mean value determined by the Hexokinase method was 106.34 while by GODAP it gave 100.29. There was a negative bias of -6.14. The linear regression analysis was performed for comparison of methods. The line of best fit was obtained. Linear correlation between the two methods was documented by calculating the correlation coefficient. The accuracy of the test method was measured by conducting a "Recovery study" on the specimen sera. The proportional error was less than the total allowable error. The P-value was found to be 0.000. Conclusion: Our study concluded that the estimation of glucose using the GOD-PAP (glucose oxidase-peroxidase) technique gave acceptable results when compared with the Hexokinase reference method. So, the validated method can be used in small and medium workload laboratories for cost-effective reliable blood glucose test results.

Estimation of foliar glucose content of areca palm by a smartphone app and Fourier transform infrared spectroscopy based multivariate modeling

Carbohydrates are essential molecules in the metabolism of plant systems whose quantification is crucial. The study aims to estimate foliar glucose content using the Smartphone-based Color Grab app by color change upon reaction with a 3,5-dinitrosalicylic acid reagent and mid-infrared spectra. The hue showed a negative correlation of − 0.959 with glucose content with sensitivity, detection limit and precision of 13.46 μg/mL,μg/mL,0.035 μg/mL, and 0.229% respectively. The glucose concentration to color coordinates displayed a linear response between 50 to 600 µg/mL. The linear regression equation with hue of standards was used to predict spectrophotometrically measured glucose concentration of leaf extracts with R2 = 0.934 and sensitivity of 13.46 μg/mL. Multivariate analysis of infrared spectrum (650–4000 cm‐1−1) of powdered arecanut leaves indicated elastic net and partial least square regression as the best models with R2 of 0.99. The study has practical implications in smartphone or infrared spectra-based glucose measurements for low glucose (< 1 mg/mL) samples.

Continuous Glucose Monitoring Reduce Duration of Hypoglycemia in Preterm Infants: A Meta-Analysis of Randomized Controlled Trials

Background: Continuous glucose monitoring (CGM) has the potential to be a valuable tool for measuring glucose concentrations in preterm neonates, but its actual effect on infants is still unclear. Therefore, we conducted a meta-analysis to evaluate the clinical effect of CGM on blood glucose levels in preterm infants requiring intensive care. Methods: We searched PubMed, Embase, CINAHL, Web of Science, Cochrane Library, and Cochrane Database of Systematic Reviews for randomized controlled trials (RCTs) comparing CGM with other interventions, and identified five studies that met our eligibility criteria. The quality of the included studies was assessed using Cochrane’s Collaboration tool. Results: Our meta-analysis demonstrated that CGM, when combined with a protocol for adjusting glucose infusion, was associated with a decrease in the average duration of hypoglycemia, a greater percentage of time spent in the euglycemic range, and reduced time spent in mild and severe hypoglycemia compared with other interventions and controls. Conclusions: Our findings suggest that CGM, with a protocol for adjusting glucose infusion, increases the time spent in the euglycemic range, and reduces the duration of hypoglycemia in preterm infants during the first week of life.

Comparison of Two Methods for the Measurement of Blood Plasma and Capillary Blood Glucose in Tropical Highland Grassing Dairy Cows.

(1) Background: There is lack of published studies validating specific cow-side glucometers such as Centrivet GK (CVGK). (2) Methods: The aims were (1) to measure and compare the blood glucose concentrations in 52 tropic highland grassing cows by using CVGK and the traditional enzymatic/photometric assay (EPA) in plasma and serum (reference method) and (2) to establish if glucose concentrations obtained via these methods could be affected by several demographic and zootechnical parameters of the dairy herd evaluated. (3) Results: Glucose concentrations were significantly (p = 0.00) affected by the method used for their measurement. The intra-assay coefficient of variation (CV) for glucose concentrations in plasma EPA and for CVGK was 14% for both methods with serum EPA, whereas the inter-assay CV for plasma EPA and CVGK was 8% and 13.7%, respectively, with serum EPA. Pearson correlation coefficient calculations between the reference method in serum and plasma presented a slightly positive significant (p = <0.000) correlation (r = 0.56), whereas there was not a significant (p = 0.413) correlation between serum EPA and CVGK (r = 0.135). The Passing and Bablok regressions were out of the ideal expected values for the slope (β = 1) and the intercept (α = 0) (11), whereas the Bland-Altman plots showed a bias of 5.29 ± 11.73 (mg/dL) for serum and plasma and 11.01 ± 15.74 (mg/dL) for serum and CVGK. The ROC curve showed no sensitivity in detecting normoglycemic cows (area = 53.7 %, e.d = 12.5 %, p = 0.759) for CVGK when compared to plasma EPA (area = 36.1 %, e.d = 14.2 %, p = 0.256). Plasma EPA exhibited a better but not significant effect in detecting hyperglycemic cows (area = 63.9%, e.d = 14.2%, p = 0.256) when compared to HHD (area = 46.3 %, e.d = 12.5 %, p = 0.759). General glucose concentrations, independently of the method used, were significantly (p = <0.001) greater in young cows when compared to adult and old cows. (4) Conclusions: Glucose concentration measurement in plasma by using EPA or in capillary blood via CVGK were not reliable methods when compared with the reference method.

Non-Invasive Glucose Sensing Technologies and Products: A Comprehensive Review for Researchers and Clinicians.

Diabetes Mellitus incidence and its negative outcomes have dramatically increased worldwide and are expected to further increase in the future due to a combination of environmental and social factors. Several methods of measuring glucose concentration in various body compartments have been described in the literature over the years. Continuous advances in technology open the road to novel measuring methods and innovative measurement sites. The aim of this comprehensive review is to report all the methods and products for non-invasive glucose measurement described in the literature over the past five years that have been tested on both human subjects/samples and tissue models. A literature review was performed in the MDPI database, with 243 articles reviewed and 124 included in a narrative summary. Different comparisons of techniques focused on the mechanism of action, measurement site, and machine learning application, outlining the main advantages and disadvantages described/expected so far. This review represents a comprehensive guide for clinicians and industrial designers to sum the most recent results in non-invasive glucose sensing techniques' research and production to aid the progress in this promising field.

Proof of concept: stabilized whole blood material suitable for external quality assessment of near-patient testing devices

Abstract Objectives Even though reliable glucose concentration measurements are essential in diagnosis and monitoring of diabetes mellitus, external quality assurance based on mandatory reference method values can only be conducted to a limited extent for measurements in whole blood. The reason is the lack of stabilized whole blood materials suitable for the application in glucose measurement devices used in near-patient testing. Methods Two patented whole blood stabilizers were tested using four commercially available near-patient testing devices and one patient self-testing device for plasma-referenced glucose measurements. Furthermore, a laboratory method for plasma-glucose measurements was included. Venous whole blood samples from 30 apparently healthy volunteers were used. Two whole blood samples (stabilizer A and B) per subject were kept at room temperature over the study period of seven days and aliquots were taken each day from the original sample for measurement on all devices. After venous puncture, left over whole blood from the collection system was used for immediate glucose measurements without stabilizer on the near-patient testing devices. Results Each investigated device gave stable results at least for one of the two stabilizers for a period of four days. Imprecision based on quality controls ranged between 1.7 and 4.8 % coefficient of variation for near-patient testing devices, but did not reflect observed variability in measurement results from stabilized and unstabilized whole blood in one device. In addition, a considerable deviation of 0.8 mmol/L was observed among the near-patient testing devices underlining the need for reference method values in external quality control. Conclusions Our study provides proof of concept that for each investigated device at least one stabilizer of glucose in whole blood shows a good performance for at least four days. Therefore, these stabilizers appear to be suitable candidate materials for external quality assessment of near-patient testing devices.

Reliability of Handheld Blood Glucose Monitors in Neonates: Trustworthy Arterial Readings but Capillary Results Warrant Caution for Hypoglycemia.

Accurate glucose monitoring is vitally important in neonatal intensive care units (NICUs) and clinicians use blood glucose monitors (BGM), such as the Inform II, for bedside glucose monitoring. Studies on BGM use in neonates have demonstrated good reliability; however, most studies only included healthy-term neonates. Therefore, the applicability of results to the preterm and/or ill neonate is limited. In preterm and ill neonates, quantify differences in glucose concentrations between (1) capillary glucose (measured by BGM) and arterial glucose (measured by YSI 2300 Stat Plus) and (2) between aliquots from the same arterial blood sample, one measured by BGM versus one by YSI. Forty neonates were included in the study. Using Inform II, we measured glucose concentrations on blood samples simultaneously collected from capillary circulation via heel puncture and from arterial circulation via an umbilical catheter. Plasma was then separated from the remainder of the arterial whole blood sample and a YSI 2300 Stat Plus measured plasma glucose concentration. The dominant majority of arterial BGM results met the Clinical and Laboratory Standard Institute (CLSI) and Food and Drug Administration (FDA) tolerance criteria. Greater discrepancy was observed with capillary BGM values with an average of 27.5% of results falling outside tolerance criteria. Blood glucose monitor testing provided reliable results from arterial blood. However, users should interpret hypoglycemic results obtained from capillary blood with caution.