Self-monitoring Blood Glucose Meters Research Articles

Evaluation of a Continuous Blood Glucose Monitor: A Novel and Non-Invasive Wearable Using Bioimpedance Technology.

Frequent blood glucose level (BGL) monitoring is essential for effective diabetes management. Poor compliance is common due to the painful finger pricking or subcutaneous lancet implantation required from existing technologies. There are currently no commercially available non-invasive devices that can effectively measure BGL. In this real-world study, a prototype non-invasive continuous glucose monitoring system (NI-CGM) developed as a wearable ring was used to collect bioimpedance data. The aim was to develop a mathematical model that could use these bioimpedance data to estimate BGL in real time. The prototype NI-CGM was worn by 14 adult participants with type 2 diabetes for 14 days in an observational clinical study. Bioimpedance data were collected alongside paired BGL measurements taken with a Food and Drug Administration (FDA)-approved self-monitoring blood glucose (SMBG) meter and an FDA-approved CGM. The SMBG meter data were used to improve CGM accuracy, and CGM data to develop the mathematical model. A gradient boosted model was developed using a randomized 80-20 training-test split of data. The estimated BGL from the model had a Mean Absolute Relative Difference (MARD) of 17.9%, with the Parkes error grid (PEG) analysis showing 99% of values in clinically acceptable zones A and B. This study demonstrated the reliability of the prototype NI-CGM at collecting bioimpedance data in a real-world scenario. These data were used to train a model that could successfully estimate BGL with a promising MARD and clinically relevant PEG result. These results will enable continued development of the prototype NI-CGM as a wearable ring.

Enzymatic Detection of Traumatic Brain Injury Related Biomarkers.

Electrochemical detection methods have been popular in the medical diagnostics field. Several well-known devices such as the self-monitoring blood glucose meter have relied on electrochemical techniques for their sensitivity, and ability to make direct measurements without optical labels. Currently, no point-of-care or handheld diagnostic tool exists to quantify the severity of a traumatic brain injury (TBI). We have shown that enzymatic detection of norepinephrine (NE), a biomarker which can indicate TBI severity, using impedance-based electrochemical techniques can achieve the required sensitivity, ∼100pg/mL. Furthermore, the first steps have been taken to quantify NE in whole blood solutions and to optimize the technique for a handheld device.

WITHDRAWN: Performance of Community Blood Glucose Meters in Calgary, Alberta: An Analysis of Quality Assurance Data.

The self-monitoring of blood glucose plays a critical role in management of diabetes mellitus. Although laboratory comparisons of glucose meter accuracy are often acceptable, clinical comparisons show frequent inaccuracies. In this paper, we evaluate the accuracy of self-monitoring blood glucose meters using glucose meter and serum comparisons from a large Canadian laboratory. This study was performed using secondary data obtained from the Laboratory Information System of Calgary Services, the sole provider of laboratory testing to Calgary and surrounding areas. We examined anonymous quality assurance data for glucose meter comparisons performed on home glucose meters between January 1, 2010, and April 30, 2013. A total of 39 542 comparisons were recorded on 18 540 different subjects. Overall, 6.7% of differences were greater than the current International Standards Organization standard of 15%, and 3.7% exceeded the Canadian guideline of 20%. Glucose meter checks were infrequently performed (on average, once per 1.6 years). A significant subset of meter results was inaccurate.

Verification of the reactivity of various sugars in self-monitoring blood glucose meters

Verification of the reactivity of various sugars in self-monitoring blood glucose meters

Development of electrochemical methods to enzymatically detect traumatic brain injury biomarkers.

As awareness of traumatic brain injury (TBI) increases, the need to detect mild forms and distinguish between the different severities of TBI becomes more apparent. The goal of this work is to develop a point-of-care sensor to detect whole blood biomarkers for rapid and sensitive diagnosis of TBI severity. Presented herein is the enzymatic detection of norepinephrine through the use of immobilization chemistry and impedance techniques. Sustained elevation of norepinephrine concentrations in the blood has been correlated to negative long-term outcomes in TBI cases, often resulting in permanent cognitive or physical deficits. Novel analysis techniques have been used to identify an optimal binding frequency (371.1 Hz) of norepinephrine to the immobilized enzyme on a gold disk electrode. This form of analysis yielded a logarithmic fit characterized by exceptional responsivity (20.89 Ω/pg mL(-1)), reproducibility (R(2)=0.96), and lower limit of detection (98 pg/mL) first in purified samples, then in rabbit whole blood solutions. Once the optimal binding frequency was determined, the preliminary use of an impedance-time technique was attempted in this work. This technique more closely resembles the amperometric detection method used in commercial self-monitoring blood glucose meters, allowing for continuous or instantaneous measurement of blood borne biomarkers without compromising sensitivity. Future directions include exploration of simultaneous multi-marker detection with the impedance-time technique and experimentation with novel mesoporous materials to filter large blood components.

Pseudohypoglycemia or hyperglycemia caused by interference with self-monitoring blood glucose measurements in anticancer ascorbic acid therapy.

Self‐monitoring blood glucose (SMBG) meters are now commonly used in diabetes management1. Many drugs, including ascorbic acid, are known to interfere with glucose measurements using these meters2. However, so far, misdiagnosis caused by interference has rarely occurred at the conventional doses. Recently, intravenous high‐dose ascorbic acid treatment has been widely used in 11,233 patients in 2006 and 8,876 patients in 2008 in the USA as one of the complementary and alternative medicines for infection and fatigue, as well as various cancers3. A 71‐year‐old woman with advanced esophageal cancer and diabetes presented to the Department of Metabolic Medicine, Osaka University Hospital, Suita, Japan, for glycemic control in November 2012. At the first visit, her glycosylated hemoglobin level was 8.8%. SMBG was carried out using the Medisafe® meter (TERUMO Corp., Tokyo, Japan) to determine the dosage of regular insulin before every meal. One day, she was given a high ascorbic acid dose (50 g) in another hospital. Her blood ascorbic acid concentration just after administration was 342 μg/mL (normal range 4.7–17.8 μg/mL), and her blood glucose level determined with the Medisafe® meter was below 1.1 mmol/L, which was ‘low’. Simultaneously, glucose levels were measured using the Glucocard® meter (ARKRAY Inc., Kyoto, Japan). According to the Glucocard® meter, her blood glucose level was above 33.3 mmol/L, which was “high.” She had neither hypoglycemic nor hyperglycemic symptoms. The fasting blood glucose level (9.3 mmol/L) determined with the Medisafe® meter 2 days after administration was close to the level (9.2 mmol/L) determined using the intra‐hospital laboratory test based on the hexokinase method (Quickauto‐Neo GLU‐HK; SHINO‐TEST Corp., Tokyo, Japan) and using an automated analyzer (JCA‐BM6050; JEOL Ltd., Tokyo, Japan). Then, the treatment with intravenous high‐dose ascorbic acid was discontinued with her consent. We prepared blood samples that contained 4.4 and 11.1 mmol/L glucose, and 0–500 μg/mL ascorbic acid. The glucose levels increased in accordance with the increased ascorbic acid concentrations using the Glucocard® meter, whereas they decreased using the Medisafe® meter. However, the glucose levels measured using the intrahospital laboratory test did not change in response to any ascorbic acid concentration (Figure 1). Figure 1 Glucose measurement interference after administration of various concentrations of ascorbic acid. Glucose concentrations were measured using Medisafe® (diamond symbols) and Glucocard® (triangular symbols) blood glucose meters, and an intra‐hospital ... The Medisafe® meter is based on the colorimetric method, which is applied to several types of Accu‐Chek® meters (Roche Diagnostics, Mannheim, Germany), whereas the Glucocard® meter is based on the electrochemical method, which is applied to many glucose meters, including the One Touch Ultra® (LifeScan Inc., Milpitas, CA, USA), FreeStyle® (Abbott Diabetes Care, Alamdea, CA, USA) and Contour® (Bayer Healthcare, Tarrytown, NY, USA) meters. As hydrogen peroxide is consumed by ascorbic acid, less hydrogen peroxide is available to react with the dye on the test strips, leading to falsely lower glucose readings by the Medisafe® meter. In contrast, ascorbic acid is oxidized at the electrode surface, and more electrons and more current are produced, leading to falsely higher glucose readings by the Glucocard® meter2. The critical glucose measurement interferences by high‐dose ascorbic acid could cause inappropriate insulin therapy or glucose administration, resulting in serious hypoglycemia or hyperglycemia. We need to understand that this type of interference occurs at the bedside; therefore, blood glucose levels just after intravenous administration of high‐dose ascorbic acid should be measured using the hexokinase method, not with these SMBG meters.

Clinical and technical evaluation of a new self-monitoring blood glucose meter: assessment of analytical and user error

Our study aimed to validate (against the standards of the American Diabetes Association and the International Organization for Standardization) the analytical and clinical accuracy of the new MediSense Precision Plus Electrodes on the QID system when compared with a reference method using the Abbott Vision glucose analyzer. Previous studies have shown that the overall accuracy of the device also depends on the proficiency of the operator, so we also assessed the ‘ease of use’ of the MediSense system, by comparing the results obtained by the patient and health care professional. Accuracy of the self-monitored blood glucose measurements was evaluated over a wide range of glucose readings (2.6–20.0 mmol/l). Between-run CVs (using the manufacturer's quality control material) were found to be 7% at 2.7 mmol/l and 4.8% at 15.5 mmol/l ( n=380). We used the error-grid analysis with target range blood glucose, then separated the data into different subsets. We found that 100% of all measurements were in the clinically acceptable zones of A and B. All measured values of the MediSense QID system complied with the requirements for ‘blood glucose monitoring meters’, as proposed by the International Organization for Standardization. The rating of the patient questionnaire showed a good to very good overall rating and acceptance with a short instruction time. The results indicate that that the MediSense QID/Precision Plus Electrodes is a reliable and easy to use device, which can be recommended for the majority of patients with diabetes mellitus.

Clinical and statistical evaluation of self-monitoring blood glucose meters.

Our objective was to compare statistical and clinical methods for the evaluation of five self-monitoring blood glucose (SMBG) meters. Two successive capillary blood glucose measurements were performed, and a simultaneous laboratory venous glucose measurement was used as the reference value. Accuracy was studied by comparing each of the two successive meter values with the reference value by 1) a Spearman's correlation test, 2) a Wilcoxon's paired test, 3) the percentage of values within the 10% interval of the reference value according to the American Diabetes Association consensus statement, and 4) the error grid analysis. The first two methods did not discriminate between the SMBG systems: r was >0.92 for the five meters, and a significant difference between the meter and reference values was found for all but one meter. The two other methods allowed classification of the devices into three groups according to their accuracy: good (two meters), acceptable (two meters), and unacceptable (one meter). These two methods gave consistent results and both had a good reproducibility, because the classification was similar for the two successive measurements. Both the Spearman's and Wilcoxon's paired tests, although commonly used, are inappropriate to evaluate SMBG systems. The percentage of SMBG values within the +/-10% interval and the error grid analysis are more accurate, because they consistently classified the five glucose meters tested in our study with a high degree of reproducibility.