Evaluation of the effects of insufficient blood volume samples on the performance of blood glucose self-test meters

Finger-Actuated Micropump of Constant Flow Rate without Backflow

This paper presents a finger-actuated micropump with a consistent flow rate and no backflow. The fluid dynamics in interstitial fluid (ISF) extraction microfluidics are studied through analytical, simulation, and experimental methods. Head losses, pressure drop, diodocity, hydrogel swelling, criteria for hydrogel absorption, and consistency flow rate are examined in order to access microfluidic performance. In terms of consistency, the experimental result revealed that after 20 s of duty cycles with full deformation on the flexible diaphragm, the output pressure became uniform and the flow rate remained at nearly constant levels of 2.2 μL/min. The flow rate discrepancy between the experimental and predicted flow rates is around 22%. In terms of diodicity, when the serpentine microchannel and hydrogel-assisted reservoir are added to the microfluidic system integration, the diodicity increases by 2% (Di = 1.48) and 34% (Di = 1.96), respectively, compared to when the Tesla integration (Di = 1.45) is used alone. A visual and experimentally weighted analysis finds no signs of backflow. These significant flow characteristics demonstrate their potential usage in many low-cost and portable microfluidic applications.

An automated all-in-one system for carbohydrate tracking, glucose monitoring, and insulin delivery

Glycemic control through titration of insulin dosing remains the mainstay of diabetes mellitus treatment. Insulin therapy is generally divided into dosing with long- and short-acting insulin, where long-acting insulin provides basal coverage and short-acting insulin supports glycemic excursions associated with eating. The dosing of short-acting insulin often involves several steps for the user including blood glucose measurement and integration of potential carbohydrate loads to inform safe and appropriate dosing. The significant burden placed on the user for blood glucose measurement and effective carbohydrate counting can manifest in substantial effects on adherence. Through the application of computer vision, we have developed a smartphone-based system that is able to detect the carbohydrate load of food by simply taking a single image of the food and converting that information into a required insulin dose by incorporating a blood glucose measurement. Moreover, we report the development of comprehensive all-in-one insulin delivery systems that streamline all operations that peripheral devices require for safe insulin administration, which in turn significantly reduces the complexity and time required for titration of insulin. The development of an autonomous system that supports maximum ease and accuracy of insulin dosing will transform our ability to more effectively support patients with diabetes.

Comparison of a human portable blood glucose meter and automated chemistry analyser for measurement of blood glucose concentrations in healthy dogs

Blood glucose measurement is one of the most commonly performed clinical diagnostic tests used to monitor glycaemia in several animal diseases. Usually, these laboratory analyses are performed on blood venous samples in remote laboratories, and the results are delayed, at best. The use of portable glucometers could evidently solve many constraints but veterinary‐use glucometers are not usually available. The present study aimed to compare blood glucose levels obtained by Bionime glucometer to the reference method using glucose oxidase. Venous blood was collected from a total number of 140 healthy dogs (72 males and 68 females), of different breeds (28 German Shepherd, 27 Pitt bull, 21 Boxer, 24 Rottweiler and 40 cross‐bred dogs) and different ages (range: 3 months–14 years) for glucose measurement using the reference laboratory method. Capillary blood samples were used to conduct a glucose measurement with a human‐use glucometer. Our results revealed that there was no significant difference between the mean capillary blood glucose (CBG) measured with the human‐use glucometer (5.06 ± 0.84 mmol/L) and the mean venous blood glucose (VBG) measured with the laboratory reference method (4.90 ± 0.73 mmol/L) (p = 0.42). Similarly, there was no significant difference of the mean CBG and VBG in male dogs (5.11 ± 0.88 and 4.97 ± 0.75 mmol/L, respectively) and female dogs (5.01 ± 0.81 and 5.07 ± 0.72 mmol/L, respectively) (p = 0.73 and 0.21, respectively), and no correlation to neither age (5.43 ± 0.90 and 5.20 ± 0.70 mmol/L in 3 to 6 month‐old dogs, 5.03 ± 0.82 and 4.94 ± 0.79 mmol/L in 6 months to 1 year‐old, 4.94 ± 0.67 and 5.13 ± 0.66 mmol/L in 1 to 4 year‐old dogs; 4.88 ± 0.94 and 4.80 ± 0.75 mmol/L in dogs older than 4 years, respectively, p < 0.05), nor to breed (4.94 ± 1.01 and 4.99 ± 0.79 mmol/L in German Shepherd, 5.13 ± 0.84 and 4.99 ± 0.79 mmol/L in Pitt Bull, 5.07 ± 0.94 and 5.07 ± 0.77 mmol/L in Boxer, 5.40 ± 0.59 and 5.48 ± 0.55 mmol/L in Rottweiler and 4.89 ± 0.75 and 4.77 ± 0.59 mmol/L in cross‐bred dogs, respectively, p < 0.05). The present study confirms that human glucometer can be used to measure glucose in dogs with a good accuracy.

Radio-Frequency Biosensors for Real-Time and Continuous Glucose Detection

This review paper focuses on radio-frequency (RF) biosensors for real-time and continuous glucose sensing reported in the literature, including our recent research. Diverse versions of glucose biosensors based on RF devices and circuits are briefly introduced, and their performances are compared. In addition, the limitations of the developed RF glucose biosensors are discussed. Finally, we present perspectives on state-of-art RF biosensing chips for point-of-care diagnosis and describe their future challenges.

Comparison of Fingertip vs Palm Site Sampling on Pain Perception, and Variation in Capillary Blood Glucose Level among Patients with Diabetes Mellitus

Introduction: Glycaemic status of the patient is often monitored using capillary blood glucose test which is fairly accurate. Traditional finger stick sampling is done to obtain sample, which can be painful and may be a barrier for repeated testing. The current study was conducted to compare fingertip and palm site sampling on pain perception, and variation in capillary blood glucose level. Methods: This study was conducted among 284 diabetic patients, who were selected by convenience sampling method. The data was collected by measuring capillary blood glucose levels from fingertip and palm site of the left hand at an interval of 10 minutes using a standard glucometer. The level of pain perceptions was measured with a numerical rating pain scale. Data analysis was accomplished using descriptive analysis, Mann-Whitney U test and Kruskal- Wallis test. Results: The level of pain perception at the palm site (2) was lesser than fingertip (3) which was significant at P < 0.001. 223 (78.52%) of the participants experienced more pain at fingertip than palm site, the difference in the measured capillary blood glucose level between fingertip [mean (SD): 226.65 (87.86)] and palm site [mean (SD): 225.65(92.13)] was minimum. The agreement of palm site was 90.7% in single measurement and 95.1% in average measurement. Conclusion: The present study concludes that, majority of the participants experienced less pain perception at the palm site sampling (alternate site sampling) than fingertip sampling with very minimal variation in the blood glucose level.

Using dried blood spot testing for diagnosing viral hepatitis

The target set by the World Health Organization to eliminate viral hepatitis as a public health problem by 2030 first requires methods of testing for hepatitis B and C virus that are acceptable to diverse populations. One such test is the dried blood spot sample method. This article explains what a dried blood spot sample is, how it is collected, and how it can help increase the viral hepatitis test uptake in prisons, drug and alcohol services, and other populations at risk of hepatitis B or C infection.

Design of an ELC resonator-based reusable RF microfluidic sensor for blood glucose estimation

Design of a reusable microfluidic sensor for blood glucose estimation at microwave frequencies is presented. The sensing unit primarily comprises a complementary electric LC (CELC) resonator, which is made reusable by filling the test sample in a glass capillary before mounting it inside a groove cut in the central arm of the resonator. The use of glass capillary in the present situation to contain the blood sample actually eliminates the possibility of any direct contact of the sensor with the test sample, and hence wards off any coincidental contamination of the sensor. Usage of the capillary provides additional benefits as only microliters of the sample are required, besides offering sterile measuring environment since these capillaries are disposable. The capillary made of borosilicate glass is highly biocompatible and exhibits exceptionally high chemical resistance in corrosive environments. Apart from reusability, the novelty of the proposed sensor also lies in its enhanced sensitivity which is quite an essential factor when it comes to the measurement of glucose concentration in the human physiological range. The applicability of the proposed scheme for glucose sensing is demonstrated by performing RF measurements of aqueous glucose solutions and goat blood samples using the fabricated sensor.

System accuracy evaluation of 18 CE-marked current-generation blood glucose monitoring systems based on EN ISO 15197:2015

OBJECTIVE

Accuracy of 18 current-generation blood glucose monitoring systems (BGMS) available in Europe was evaluated applying criteria adapted from EN ISO 15197:2015 with one reagent system lot. BGMS were selected based on market research data.

RESEARCH DESIGN AND METHODS

The BGMS ABRA, Accu-Chek Guide, AURUM, CareSens Dual, CERA-CHEK 1CODE, ContourNext One, eBsensor, FreeStyle Freedom Lite, GL50 evo, GlucoCheck GOLD, GlucoMen areo 2K, GluNEO, MyStar DoseCoach, OneTouch Verio Flex, Pic GlucoTest, Rightest GM700S, TRUEyou, and WaveSense JAZZ Wireless were tested using capillary blood from 100 different subjects and assessing the percentage of results within ±15 mg/dL (0.83 mmol/L) or 15% of comparison method results for BG concentrations below or above 100 mg/dL (5.55 mmol/L), respectively. In addition, the minimal deviation from comparison method results within which ≥95% of results of the respective BGMS were found was calculated.

RESULTS

In total, 14 BGMS had ≥95% of results within ±15 mg/dL (0.83 mmol/L) or ±15% and 3 BGMS had ≥95% of results within ±10 mg/dL (0.55 mmol/L) or ±10% of the results obtained with the comparison method. The smallest deviation from comparison method results within which ≥95% of results were found was ±7.7 mg/dL (0.43 mmol/L) or ±7.7%; the highest deviation was ±19.7 mg/dL (1.09 mmol/L) or ±19.7%.

CONCLUSIONS

This accuracy evaluation shows that not all CE-labeled BGMS fulfill accuracy requirements of ISO 15197 reliably and that there is considerable variation even among BGMS fulfilling these criteria. This safety-related information should be taken into account by patients and healthcare professionals when making therapy decisions.

TRIAL REGISTRATION NUMBER

NCT03737188.

Accuracy of a blood glucose monitoring system that recognizes insufficient sample blood volume and allows application of more blood to the same test strip

Background: Self-monitoring of blood glucose (SMBG) can play a key role in diabetes management. The CONTOUR®NEXT ONE (Ascensia Diabetes Care, Parsippany, NJ, USA) blood glucose monitoring system (BGMS) has been developed for use with CONTOUR®NEXT test strips. The meter connects to the CONTOUR™ Diabetes application on a mobile device, and the Second-Chance® sampling feature recognizes insufficient sample volume, prompting the patient to apply more blood to the same strip if needed (sample re-application).Research design and methods: Two studies evaluated CONTOUR®NEXT ONE BGMS accuracy with sample re-application: a laboratory study (performance under various controlled conditions) and a clinical study (performance in the hands of 52 people with diabetes). A formal International Organization for Standardization (ISO) evaluation has been reported previously; here, accuracy criteria in the laboratory and clinical studies were aligned with ISO 15197:2013 sections 6.3.3 and 8.2, respectively.Results: All results under all conditions in the laboratory study, and with glucose concentrations <100 and ≥100 mg/dL in the clinical study, were within ±15 mg/dL or ±15% of reference measurements. In both studies, all results were within Zone A of the Parkes-Consensus Error Grid.Conclusions: These data demonstrate that the accuracy of the CONTOUR®NEXT ONE BGMS was maintained with sample re-application.

Challenges and perspectives in continuous glucose monitoring

Diabetes is a global epidemic that threatens the health and well-being of hundreds of millions of people. The first step in patient treatment is to monitor glucose levels. Currently this is most commonly done using enzymatic strips. This approach suffers from several limitations, namely it requires a blood sample and is therefore invasive, the quality and the stability of the enzymatic strips vary widely, and the patient is burdened by performing the measurement themselves. This results in dangerous fluctuations in glucose levels often going undetected. There is currently intense research towards new approaches in glucose detection that would enable non-invasive continuous glucose monitoring (CGM). In this review, we explore the state-of-the-art in glucose detection technologies. In particular, we focus on the physical mechanisms behind different approaches, and how these influence and determine the accuracy and reliability of glucose detection. We begin by reviewing the basic physical and chemical properties of the glucose molecule. Although these play a central role in detection, especially the anomeric ratio, they are surprisingly often overlooked in the literature. We then review state-of-the art and emerging detection methods. Finally, we survey the current market for glucometers. Recent results show that past challenges in glucose detection are now being overcome, thereby enabling the development of smart wearable devices for non-invasive continuous glucose monitoring. These new directions in glucose detection have enormous potential to improve the quality of life of millions of diabetics, as well as offer insight into the development, treatment and even prevention of the disease.

Evaluation of Accuracy of Six Blood Glucose Monitoring Systems and Modeling of Possibly Related Insulin Dosing Errors

OBJECTIVE

Self-monitoring of blood glucose (BG) is an essential part of diabetes therapy. Accurate and reliable results from BG monitoring systems (BGMS) are important especially when they are used to calculate insulin doses. This study aimed at assessing system accuracy of BGMS and possibly related insulin dosing errors.

RESEARCH DESIGN AND METHODS

System accuracy of six different BGMS (Accu-Chek^® Aviva Nano, Accu-Chek Mobile, Accu-Chek Performa Nano, CONTOUR^® NEXT LINK 2.4, FreeStyle Lite, OneTouch^® Verio^® IQ) was assessed in comparison to a glucose oxidase and a hexokinase method. Study procedures and analysis were based on ISO 15197:2013/EN ISO 15197:2015, clause 6.3. In addition, insulin dosing error was modeled.

RESULTS

In the comparison against the glucose oxidase method, five out of six BGMS fulfilled ISO 15197:2013 accuracy criteria. Up to 14.3%/4.3%/0.3% of modeled doses resulted in errors exceeding ±0.5/±1.0/±1.5 U and missing the modeled target by 20 mg/dL/40 mg/dL/60 mg/dL, respectively. Compared against the hexokinase method, five out of six BGMS fulfilled ISO 15197:2013 accuracy criteria. Up to 25.0%/10.5%/3.2% of modeled doses resulted in errors exceeding ±0.5/±1.0/±1.5 U, respectively.

CONCLUSIONS

Differences in system accuracy were found, even among BGMS that fulfilled the minimum system accuracy criteria of ISO 15197:2013. In the error model, considerable insulin dosing errors resulted for some of the investigated systems. Diabetes patients on insulin therapy should be able to rely on their BGMS' readings; therefore, they require highly accurate BGMS, in particular, when making therapeutic decisions.

Clinical review: the misreporting of logbook, download, and verbal self-measured blood glucose in adults and children with type I diabetes

Despite advances in technology, the frequent self-measurement of blood glucose (SMBG) remains fundamental to the management of 1 diabetes mellitus (T1DM). Once measured, SMBG results are routinely reported back to health professionals and other interested parties, either verbally, via a logbook, or electronically downloaded from a pump or meter. The misreporting of SMBG using various techniques represents a classic non-adherence behavior and carries with it both acute and chronic dangers. In addition, while this behavior appears very prevalent, many aspects remain largely unstudied. With this in mind, we aimed to summarize literature addressing the misreporting of SMBG in T1DM via a detailed literature search. This produced both recent and past literature. While most of these studies examined the prevalence of deliberate misreporting in a verbal or logbook context, others focused on the motivations behind this behavior, and alternative forms of misreporting, including deliberate manipulation of meters to produce inaccurate results and true technological errors. This timely review covers all aspects of misreporting and highlights multiple patient techniques, which are clearly adapting to advances in technology. We believe that further understanding and attention to this aspect of adherence may lead not only to improvements in glycemic control and safety, but also to the psychological well-being of those affected by type 1 diabetes.

Promoting health and reducing costs: a role for reform of self-monitoring of blood glucose provision within the National Health Service

AIM

To determine the cost-effectiveness of all options for the self-monitoring of blood glucose funded by the National Health Service, providing guidance for disinvestment and testing the hypothesis that advanced meter features may justify higher prices.

METHODS

Using data from the Health and Social Care Information Centre concerning all 8 340 700 self-monitoring of blood glucose-related prescriptions during 2013/2014, we conducted a cost-minimization analysis, considering both strip and lancet costs, including all clinically equivalent technologies for self-monitoring of blood glucose, as determined by the ability to meet ISO-15197:2013 guidelines for meter accuracy.

RESULTS

A total of 56 glucose monitor, test strip and lancet combinations were identified, of which 38 met the required accuracy standards. Of these, the mean (range) net ingredient costs for test strips and lancets were £0.27 (£0.14-£0.32) and £0.04 (£0.02-£0.05), respectively, resulting in a weighted average of £0.28 (£0.18-£0.37) per test. Systems providing four or more advanced features were priced equal to those providing just one feature. A total of £12 m was invested in providing 42 million self-monitoring of blood glucose tests with systems that fail to meet acceptable accuracy standards, and efficiency savings of £23.2 m per annum are achievable if the National Health Service were to disinvest from technologies providing lesser functionality than available alternatives, but at a much higher price.

CONCLUSION

The study uncovered considerable variation in the price paid by the National Health Service for self-monitoring of blood glucose, which could not be explained by the availability of advanced meter features. A standardized approach to self-monitoring of blood glucose prescribing could achieve significant efficiency savings for the National Health Service, whilst increasing overall utilisation and improving safety for those currently using systems that fail to meet acceptable standards for measurement accuracy.

AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS AND AMERICAN COLLEGE OF ENDOCRINOLOGY 2016 OUTPATIENT GLUCOSE MONITORING CONSENSUS STATEMENT

This document represents the official position of the American Association of Clinical Endocrinologists and American College of Endocrinology. Where there were no randomized controlled trials or specific U.S. FDA labeling for issues in clinical practice, the participating clinical experts utilized their judgment and experience. Every effort was made to achieve consensus among the committee members. Position statements are meant to provide guidance, but they are not to be considered prescriptive for any individual patient and cannot replace the judgment of a clinician.