Portable Glucose Research Articles

Highly sensitive detection of mercury ion based on T-rich DNA machine using portable glucose meter

Mercury ion (Hg2+) has threats to human health and the environment even at a low concentration, thus it is desirable to propose a sensitive and portable method to detect it. In this work, it could realize detection of Hg2+ at low femtomolar concentration. Thymine-thymine (T-T) mismatches oligodeoxyribonucleotides were employed as specific recognition elements for selectively capturing Hg2+ to form hairpin structure and triggering the T-rich DNA machine operation to produce a large amount of product DNA for signal amplification. Product DNA connected capture DNA (Capt-DNA) with DNA-invertase conjugation which catalyzed sucrose into glucose. Thus, the output portable glucose meter (PGM) signals which came from glucose is related with the amount of product DNA, indirectly quantifying the concentration of Hg2+. It is shown that the detection limit of this method is as low as 10−17M and linear range is 10−6–10−17M without any complicated instrument. What’s more, this novel method could be applied in highly sensitive and selective Hg2+ detection in fish samples. Therefore, owing to the simple operability and portable use of PGM, this method is expected to have a wide application in routine detection the concentration of Hg2+ in environmental water and biologic samples in everyone’s home.

The using status quo and analysis of POCT glucose meter

Objective To investigate the problems during using, standard and quality management of the POCT glucose meters in hospital, to analyze the solutions, and to provide reference data for improving the test level of POCT in hospital. Methods The amount, brand and application of portable glucose meters in the hospital were obtained by 3 rounds of surveillance from May to July in 2013. All of those glucose meters were taken part in external quality assessment of Clinical Laboratory Center of National Health and Family Planning Commission. The test results of those glucose meters were compared with that of automatic biochemical analyzer, the comparison results were then analyzed. Results The POCT glucose meters possessed 5 brands in our hospital, and the amount and type of glucose meters in some clinical departments were often changed. When 4 brands which were detected as quality control samples by ministry of health, the accuracy of detection results of 3 concentration of brand Ⅲ were substandard, the CV% of two levels were 11.9% and 10.1% respectively, the remaining 3 brands were in line with the requirements. The qualified percentages of 3 times of comparison were 85.0%, 92.0% and 97.4%. Conclusions The hospital should select the brand of portable glucose meters reasonably, correct use of glucose meters, and it is very necessary to build indoor and interstitial quality evaluation system, at the same time, suggesting the hospital to establish the POCT quality management team, to carry out the instrument comparison periodically, so to guarantee the accurate, reliable results of POCT in hospital.(Chin J Lab Med, 2016, 39: 643-645) Key words: Glucose tolerance test; Monitoring, ambulatory; Point-of-care systems; Quality assurance, health care

Pin-based electrochemical glucose sensor with multiplexing possibilities

This work describes the use of mass-produced stainless-steel pins as low-cost electrodes to develop simple and portable amperometric glucose biosensors. A potentiostatic three-electrode configuration device is designed using two bare pins as reference and counter electrodes, and a carbon-ink coated pin as working electrode. Conventional transparency film without any pretreatment is used to punch the pins and contain the measurement solution. The interface to the potentiostat is very simple since it is based on a commercial female connection. This electrochemical system is applied to glucose determination using a bienzymatic sensor phase (glucose oxidase/horseradish peroxidase) with ferrocyanide as electron-transfer mediator, achieving a linear range from 0.05 to 1mM. It shows analytical characteristics comparable to glucose sensors previously reported using conventional electrodes, and its application for real food samples provides good results. The easy modification of the position of the pins allows designing different configurations with possibility of performing simultaneous measurements. This is demonstrated through a specific design that includes four pin working-electrodes. Different concentrations of antibody labeled with alkaline phosphatase are immobilized on the pin-heads and after enzymatic conversion of 3-indoxylphosphate and silver nitrate, metallic silver is determined by anodic stripping voltammetry.

Diagnosis of prediabetes in cats: glucose concentration cut points for impaired fasting glucose and impaired glucose tolerance

Diabetes is typically diagnosed in cats once clinical signs are evident. Diagnostic criteria for prediabetes in cats have not been defined. The objective of the study was to establish methodology and cut points for fasting and 2-h blood glucose concentrations in healthy client-owned senior cats (≥8 yr) using ear/paw samples and a portable glucose meter calibrated for feline blood. Of the 78 cats, 27 were ideal (body condition score [BCS] 4 or 5 of 9), 31 overweight (BCS 6 or 7), and 20 obese (BCS 8 or 9); 19 were Burmese and 59 non-Burmese. After an 18–24-h fast and an ear/paw blood glucose measurement using a portable glucose meter, glucose (0.5 g/kg bodyweight) was administered intravenous and blood glucose measured at 2 min and 2 h. Cut points for fasting and 2-h glucose concentrations were defined as the upper limits of 95% reference intervals using cats with BCS 4 or 5. The upper cut point for fasting glucose was 6.5 mmol/L. Of the overweight and obese cats, 1 (BCS 7) was above this cut point indicating evidence of impaired fasting glucose. The cut point for 2-h glucose was 9.8 mmol/L. A total of 7 cats (4 with BCS 8 or 9 including 1 Burmese; 3 with BCS 6 or 7, non-Burmese) were above this cut point and thus had evidence of impaired glucose tolerance. In conclusion, the methodology and cutpoints for diagnosis of prediabetes are defined for use in healthy cats 8 yr and older with a range of BCSs.

Highly Sensitive Metabolite Biosensor Based on Organic Electrochemical Transistor Integrated with Microfluidic Channel and Poly(N‐vinyl‐2‐pyrrolidone)‐Capped Platinum Nanoparticles

Organic electrochemical transistors (OECTs) are used as highly sensitive glucose and lactate sensors by modifying the gate electrode with glucose oxidase/lactate oxidase and poly(n‐vinyl‐2‐pyrrolidone)‐capped platinum nanoparticles (Pt NPs). The Pt NPs are deposited by using a two‐step dip coating method without bias instead of the conventional electrodeposition method and followed by an UV‐Ozone post treatment to enhance the catalytic ability of the Pt NPs. The modified OECT sensors have extremely high sensitivity, and can achieve a detection limit of glucose and lactate down to 10−7 and 10−6m, respectively. A polydimethylsiloxane microfluidic channel is successfully integrated with the OECT sensors, which provides a compact chip size of the sensors, a short detection time of around 1 min and extremely low consumption of analyte (30 L). The cross talk between individual sensors in multianalyte sensing devices is also reduced by the dual microfluidic channel structure. Practical applications, such as for detecting glucose in saliva, can therefore be realized, and a prototype of a portable glucose sensor has been successfully created in this study. This portable glucose sensor has excellent potential for real‐time and noninvasive glucose sensing applications.

Graphene-based field effect transistor enzymatic glucose biosensor using silk protein for enzyme immobilization and device substrate

A silk fibroin-encapsulated graphene field effect transistor (FET) enzymatic biosensor that utilizes silk protein as both device substrate and enzyme immobilization material was developed for glucose detection. This biosensor detected glucose levels by measuring the differential drain-source current and the Dirac point shift of the graphene transistor as the glucose is oxidized by glucose oxidase that was immobilized in silk fibroin film on the graphene FET. The fabricated biosensors showed 0.1–10mM large linear detection range, which covers the reference range of medical examination for diabetes diagnostics. The detection limit of the fabricated biosensors was approximately 0.1mM (S/N=3) with excellent selectivity, and the average sensitivity was 2.5μA/mM measured at Vds=100mV and Vg=0V. Because this fibroin-encapsulated graphene FET enzymatic biosensor is biocompatible, flexible, and long-term stable, it holds a great promise for portable, wearable, and implantable continuous glucose monitoring applications.

Hypoglycemia in type 2 diabetes patients treated with insulin: the advantages of continuous glucose monitoring

Aims. To determine the incidence and risk factors for hypoglycemia in elderly insulin-treated type 2 diabetes mellitus (T2DM) patients by means of continuous glucose monitoring (CGM). Materials and Methods. We observed seventy-six hospitalized patients with T2DM, aged 65 to 79 years. Treatment with basal insulin (n=36), premixed insulin (n=12) or basal-bolus insulin regimen (n=28) was followed by metformin (n=44), glimepiride (n=14) and dipeptidyl peptidase-4 inhibitors (n=14). 2-days CGM with retrospective data analysis was performed in all patients. During CGM, three fasting and three 2-h postprandial finger-prick glucose values were obtained daily with portable glucose meter. Results. Hypoglycemia (identified as blood glucose

Nanoparticle-based pseudo hapten for target-responsive cargo release from a magnetic mesoporous silica nanocontainer.

A novel homogeneous immunoassay method is developed for sensitive monitoring of small molecular biotoxin by using a portable personal glucose meter (PGM) based on the target-responsive release of cargo (glucose) from a polystyrene microsphere-gated magnetic mesoporous nanocontainer.

Validity of a Portable Glucose, Total Cholesterol, and Triglycerides Multi-Analyzer in Adults

This study investigated the accuracy and precision of the Accutrend Plus system to determine blood glucose, total cholesterol, and plasma triglycerides in adults and evaluated its efficiency in measuring these blood variables. The sample consisted of 53 subjects (≥ 18 years). For blood variable laboratory determination, venous blood samples were collected and processed in a Labmax 240 analyzer. To measure blood variables with the Accutrend Plus system, samples of capillary blood were collected. In the analysis, the following tests were included: Wilcoxon and Student's t-tests for paired samples, Lin's concordance coefficient, Bland-Altman method, receiver operating characteristic curve, McNemar test, and k statistics. The results show that the Accutrend Plus system provided significantly higher values (p ≤ .05) of glucose and triglycerides but not of total cholesterol (p > .05) as compared to the values determined in the laboratory. However, the system showed good reproducibility (Lin's coefficient: glucose = .958, triglycerides = .992, total cholesterol = .940) and high concordance with the laboratory method (Lin's coefficient: glucose = .952, triglycerides = .990, total cholesterol = .944) and high sensitivity (glucose = 80.0%, triglycerides = 90.5%, total cholesterol = 84.4%) and specificity (glucose = 100.0%, triglycerides = 96.9%, total cholesterol = 95.2%) in the discrimination of high values of the three blood variables analyzed. It could be concluded that despite the tendency to overestimate glucose and triglyceride levels, a portable multi-analyzer is a valid alternative for the monitoring of metabolic disorders and cardiovascular risk factors.

The use of an automated, portable glucose control system for overnight glucose control in adolescents and young adults with type 1 diabetes.

OBJECTIVEA key milestone in progress towards providing an efficacious and safe closed-loop artificial pancreas system for outpatient use is the development of fully automated, portable devices with fault detection capabilities to ensure patient safety. The ability to remotely monitor the operation of the closed-loop system would facilitate future physician-supervised home studies.RESEARCH DESIGN AND METHODSThis study was designed to investigate the efficacy and safety of a fully automated, portable, closed-loop system. The Medtronic Portable Glucose Control System (PGCS) consists of two subcutaneous glucose sensors, a control algorithm based on proportional-integral-derivative with insulin feedback operating from a BlackBerry Storm smartphone platform, Bluetooth radiofrequency translator, and an off-the-shelf Medtronic Paradigm Veo insulin pump. Participants with type 1 diabetes using insulin pump therapy underwent two consecutive nights of in-clinic, overnight, closed-loop control after a baseline open-loop assessment.RESULTSEight participants attended for 16 overnight studies. The PGCS maintained mean overnight plasma glucose levels of 6.4 ± 1.7 mmol/L (115 ± 31 mg/dL). The proportion of time with venous plasma glucose <3.9, between 3.9 and 8 (70 and 144 mg/dL), and >8 mmol/L was 7, 78, and 15%, respectively. The proportion of time the sensor glucose values were maintained between 3.9 and 8 mmol/L was greater for closed-loop than open-loop (84.5 vs. 46.7%; P < 0.0001), and time spent <3.3 mmol/L was also reduced (0.9 vs. 3%; P < 0.0001).CONCLUSIONSThese results suggest that the PGCS, an automated closed-loop device, is safe and effective in achieving overnight glucose control in patients with type 1 diabetes.

Clinical value of blood glucose measurement in pet rabbits

Blood glucose was measured with a portable glucose meter in 907 rabbits, including 238 clinically healthy ones. Blood glucose concentrations ranged from 1.2 to 30.1 mmol/l. Diabetes mellitus was not...

Flexible glucose sensor using CVD-grown graphene-based field effect transistor

A flexible glucose sensor using a CVD-grown graphene-based field-effect-transistor (FET) is demonstrated. The CVD-grown graphene was functionalized with linker molecules in order to immobilize the enzymes that induce the catalytic response of glucose. Polyethylene terephthalate (PET) was employed as the substrate material to realize a flexible sensor. The fabricated graphene-based FET sensor showed ambipolar transfer characteristics. Through measurements of the Dirac point shift and differential drain-source current, the fabricated FET sensor could detect glucose levels in the range of 3.3–10.9mM, which mostly covers the reference range of medical examination or screen test for diabetes diagnostic. This CVD-grown graphene-based FET sensor, which provides excellent fitting to a model curve even when deformed, high resolution, and continuous real-time monitoring, holds great promise, especially for portable, wearable, and implantable glucose level monitoring applications.

Novel amperometric glucose biosensor based on covalent immobilization of glucose oxidase on poly(pyrrole propylic acid)/Au nanocomposite

A glucose biosensor is fabricated with immobilization of glucose oxidase (GOx) on poly(pyrrole propylic acid)/Au nanocomposite by covalent attachment. Poly(pyrrole propylic acid) (PPyAA)/Au nanocomposite was prepared by chemical oxidation of pyrrole propylic acid monomer by using chloroauric acid (HAuCl4) as an oxidizing agent. The obtained nanocomposites were used to fabricate highly sensitive amperometric glucose biosensor which exhibited a high and reproducible sensitivity of 0.42μA/mM, response time ∼2s, linear dynamic range from 1 to 18mM, correlation coefficient of R2=0.9981, and limit of detection (LOD), based on S/N ratio (S/N=3) of 0.05mM. A value of 1.83mM for the apparent Michaelis–Menten constant Kmapp was obtained. The high sensitivity, wider linear range, good reproducibility and stability make this biosensor a promising candidate for portable amperometric glucose biosensor.

Accuracy of a portable glucose meter and of a Continuous Glucose Monitoring device used at home by patients with type 1 diabetes

BackgroundPatients with diabetes are recommended to self-monitor their blood glucose levels also at home. Accuracy of a hand-held glucometer and a Continuous Glucose Monitoring (CGM) device were comparatively evaluated. MethodsVenous blood samples (for reference laboratory determinations; n=428) were collected from 18 type 1 patients (35–65years old), immediately followed by capillary measurement (Bayer ContourLink meter) and CGM readings (Medtronic Paradigm). ResultsLaboratory values did not differ statistically from ContourLink and CGM readings, mean difference (±SD) being −0.05±1.06mmol/L and 0.10±1.84mmol/L glucose, respectively. A bias ((value−reference)/reference×100) ≥15% was observed in 27.7% and 54.9% of cases, respectively. Notably, below 3.9mmol/L glucose (hypoglycemic threshold), an absolute error>0.8mmol/L was found in 78.9% and 94.1% of cases. The absolute errors of the CGM device were inversely related to the rate of glucose change (r=0.598, p<0.001). ConclusionsA very large error was observed at the extreme glycemic values, which may lead to erroneous therapy. Consequently, performance of future portable glucometers should be focused in particular under hypo- and hyper-glycemia. Moreover, integrated CGM devices should not disregard the effect of the rate of blood glucose change on the sensor readings.

Evaluation of a portable glucose meter for use in cattle and sheep

In farm animal practice, determination of blood glucose concentration under field conditions is often necessary. As there is no portable glucose meter device developed for use in farm animals, the analytical accuracy of a portable glucometer designed for people was evaluated for its use in cattle and sheep. Blood samples from 90 cattle and 101 sheep were used in the study. Glucose concentration was determined in whole blood immediately after blood collection from the jugular vein with the One Touch Vita portable glucometer and in serum with an enzymatic colorimetric method. The agreement between methods was assessed by Passing and Bablok regression analysis. The precision and the accuracy of the measurements were determined using the concordance correlation coefficient. There was a strong linear relationship between the glucose values obtained using the portable glucometer and those obtained by the bench method in both cattle and sheep. Precision was 95% for cattle and 88% for sheep, whereas accuracy was 92% and 99%, respectively. The mean glucose values obtained using the portable glucometer were significantly lower by 8.3% in cattle and 3.2% in sheep than those determined by the bench method. The One Touch Vita portable glucometer can be used in clinical practice to determine blood glucose concentrations in cattle and sheep, but reference intervals (RI) must be corrected to allow for negative bias. Based on these equations the RI for blood glucose in cattle and sheep using the portable glucometer were corrected to 1.84-4.17 and 2.41-4.35 mmol/L, respectively.

Evaluation of hematocrit bias on blood glucose measurement with six different portable glucose meters

Measurement and monitoring of blood glucose levels in hospitalized patients with portable glucose meters (PGMs) is performed widely and is an essential part of diabetes monitoring, despite the increasing evidence of several interferences which can negatively bias the accuracy of measurements. The purpose of this study was to evaluate the effect of the hematocrit on the analytical performances of different PGMs as compared with a reference laboratory assay. The effect of various hematocrit values (approximiately 0.20, approximiately 0.45 and approximiately 0.63 L/L) were assessed in three whole blood specimens with different glucose concentration (approximiately 1.1, approximiately 13.3, and approximiately 25 mmol/L) by using six different commercial PGMs. The identical samples were also tested with the laboratory reference assay (i.e., hexokinase). The percentage difference from the laboratory assay (%Diff) was calculated as follows: % Diff = average PGM value - value from laboratory assay x 100 / value from laboratory assay. The %Diff of the six different PGMs were rather broad, and comprised between 56.5% and -34.8% in the sample with low glucose concentration (approximiately 1.1 mmol/L), between 40% and -32% in the sample with high glucose concentration (approximiately 13.3 mmol/L), and between -50% and 15% in the sample with very high glucose concentration (approximiately 25 mmol/L), respectively. It is also noteworthy that a very high hematocrit value (up to 0.63 L/L) generated a remarkable negative bias in blood glucose (-35%) as measured with the laboratory assay, when compared with the reference sample (hematocrit 0.45 L/L). The results of this analytical evaluation clearly confirm that hematocrit produces a strong and almost unpredictable bias on PGMs performances, which is mainly dependent on the different type of devices. As such, the healthcare staff and the patients must be aware of this limitation, especially in the presence of extreme hematocrit levels, when plasma glucose assessment with the reference laboratory technique might be advisable.

Reducing patient identification errors related to glucose point-of-care testing

Background: Patient identification (ID) errors in point-of-care testing (POCT) can cause test results to be transferred to the wrong patient’s chart or prevent results from being transmitted and reported. Despite the implementation of patient barcoding and ongoing operator training at our institution, patient ID errors still occur with glucose POCT. The aim of this study was to develop a solution to reduce identification errors with POCT. Materials and Methods: Glucose POCT was performed by approximately 2,400 clinical operators throughout our health system. Patients are identified by scanning in wristband barcodes or by manual data entry using portable glucose meters. Meters are docked to upload data to a database server which then transmits data to any medical record matching the financial number of the test result. With a new model, meters connect to an interface manager where the patient ID (a nine-digit account number) is checked against patient registration data from admission, discharge, and transfer (ADT) feeds and only matched results are transferred to the patient’s electronic medical record. With the new process, the patient ID is checked prior to testing, and testing is prevented until ID errors are resolved. Results: When averaged over a period of a month, ID errors were reduced to 3 errors/month (0.015%) in comparison with 61.5 errors/month (0.319%) before implementing the new meters. Conclusion: Patient ID errors may occur with glucose POCT despite patient barcoding. The verification of patient identification should ideally take place at the bedside before testing occurs so that the errors can be addressed in real time. The introduction of an ADT feed directly to glucose meters reduced patient ID errors in POCT.

Glucose Biosensor Based on the Fabrication of Glucose Oxidase in the Bio‐Inspired Polydopamine‐Gold Nanoparticle Composite Film

AbstractA highly efficient enzyme immobilization method has been developed for electrochemical biosensors using polydopamine films with gold nanoparticles (AuNPs) embedded. This simple enzyme fabrication method can be performed in very mild conditions and stored in a long time with high bioactivity. The fabricated amperometric glucose biosensor exhibited a high and reproducible sensitivity, wide linear dynamic range and low limit of detection (LOD) (0.1 μmol·L−1). A low value of 1.5 mmol·L−1 for the apparent Michaelis‐Menten constant KappM was obtained. The high sensitivity, wide linear range, good reproducibility and stability make this biosensor a promising candidate for portable amperometric glucose biosensor.

Evaluation of a new portable glucose meter designed for the use in cats

Portable blood glucose meters (PBGMs) are useful in the management of diabetes mellitus in cats. In the present study we compared the performance of two PBGMs: the AlphaTRAK (Abbott Animal Health, Maidenhead, England) specifically developed for dogs and cats, and the Ascensia ELITE (Bayer HealthCare, Zurich, Switzerland) developed for humans. Quality parameters, including precision and accuracy, were better for the AlphaTRAK meter compared to Ascensia ELITE. While the AlphaTRAK meter results did not differ from the reference method, results from the Ascensia ELITE were significantly (P<0.001) lower. The superior performance of the AlphaTRAK meter supports its use to monitor blood glucose levels in cats.

Tight Glucose Control in Critically Ill Patients: Should Glucose Meters Be Used?

Measurement of blood glucose concentrations using portable, hand-held meters is used widely in patients with diabetes. Clinical settings include self-monitoring of blood glucose by patients, in doctors’ offices, in chronic care facilities, and in hospitals. More recently, evidence has emerged suggesting that tight glycemic control of nondiabetic patients in hospital intensive care units (ICUs)1 improves clinical outcomes. Based on this evidence, lowering blood glucose concentrations with insulin has become the standard of care in many ICUs and other hospital settings. In the vast majority of these patients, frequent measurements of blood glucose are performed with portable glucose meters, and the values are used to determine the dose of insulin. In this Q&A article, 5 experts in the field are asked to comment on the use of glucose meters in tight glycemic control. Greet Van den Berghe2 : This depends on the definition of “tight” and what is meant by “hospitalized.” Although there are numerous studies showing a strong association of both hyperglycemia and hypoglycemia with mortality in hospitalized patients (the nadir of the risk being associated with the “normal for age” fasting blood glucose range), the evidence from randomized controlled studies currently comes from those performed in ICU patients. The 3 studies that we performed in Leuven compared a “normal (fasting) for age” target for blood glucose [80–110 mg/dL (4.4–6.1 mmol/L) for adults, 70–100 mg/dL (3.9–5.6 mmol/L) for children, and 50–80 mg/dL (2.8–4.4 mmol/L) for infants] with a control group in which we assumed hyperglycemia to be a potentially beneficial adaptation. In the control group, we therefore used a “do not touch” approach unless glucose exceeded the renal threshold of 215 mg/dL (11.9 mmol/L). Blood glucose was measured with only 1 device, namely an ABL blood gas analyzer in the surgical and pediatric ICU studies and the HemoCue …