Performance evaluation of a self-administered home oral glucose tolerance test kit in a controlled clinical research setting.

AIM: To evaluate the performance of the current, pre-production version of a novel home oral glucose tolerance test (Home OGTT) device when administered by trained research nurses, compared with a reference laboratory glucose analyser and a second laboratory analyser, incorporating a sample processing delay to simulate normal practice. METHODS: One hundred women (aged 19-48 years), with and without known glucose intolerance were recruited. Following an overnight fast, participants attended for a 75-g OGTT. A fasting capillary sample was applied to the Home OGTT device with a corresponding venous sample collected and measured immediately on the reference YSI 2300 stat plus analyser, and following a 1-h delay on the Randox Daytona Plus analyser. The sampling process was repeated 2 h after the oral glucose load. RESULTS: Some 97% of tested devices gave complete data for analysis. Good agreement was observed between the reference glucose analyser and the Home OGTT device, with the Home OGTT device displaying a small negative bias (-0.18 mmol/l, -1.75 to 1.39 mmol/mol; -1.0%, -26.4% to 24.5%; absolute and relative mean, 95% limits of agreement). When classified as normal glucose tolerant or glucose intolerant, the Home OGTT device showed 100% and 90% sensitivity, and 99% and 99% specificity using fasting plasma glucose and 2-h glucose respectively. Similar sensitivity (100% and 100%) and specificity (96% and 99%) for fasting plasma glucose and 2-h glucose were observed using the secondary analyser. CONCLUSIONS: The novel Home OGTT device was reliable and easy to use and showed excellent agreement with two separate laboratory analysers. The Home OGTT offers potential as an effective alternative for clinic-based OGTT testing.

Statistical and spectral analysis of ECG signal towards achieving non-invasive blood glucose monitoring.

BACKGROUND: Globally, the cases of diabetes mellitus (diabetes) have increased in the past three decades, and it is recorded as one of the leading cause of death. This epidemic is a metabolic condition where the body cannot regulate blood glucose, thereby leading to abnormally high blood sugar. Genetic condition plays a significant role to determine a person susceptibility to the condition, a sedentary lifestyle and an unhealthy diet are behaviour that supports the current global epidemic. The complication that arises from diabetes includes loss of vision, peripheral neuropathy, cardiovascular complications and so on. Victims of this condition require constant monitoring of blood glucose which is done by the pricking of the finger. This procedure is painful, inconvenient and can lead to disease infection. Therefore, it is important to find a way to measure blood glucose non-invasively to minimize or eliminate the disadvantages encountered with the usual monitoring of blood glucose. METHOD: In this paper, we performed two experiments on 16 participants while electrocardiogram (ECG) data was continuously captured. In the first experiment, participants are required to consume 75 g of anhydrous glucose solution (oral glucose tolerance test) and the second experiment, no glucose solution was taken. We explored statistical and spectral analysis on HRV, HR, R-H, P-H, PRQ, QRS, QT, QTC and ST segments derived from ECG signal to investigate which segments should be considered for the possibility of achieving non-invasive blood glucose monitoring. In the statistical analysis, we examined the pattern of the data with the boxplot technique to reveal the change in the statistical properties of the data. Power spectral density estimation was adopted for the spectral analysis to show the frequency distribution of the data. RESULTS: HRV segment obtained a statistical score of 81% for decreasing pattern and HR segment have the same statistical score for increasing pattern among the participants in the first quartile, median and mean properties. While ST segment has a statistical score of 81% for decreasing pattern in the third quartile, QT segment has 81% for increasing pattern for the median. From a total change score of 6, ST, QT, PRQ, P-H, HR and HRV obtained 4, 5, 4, 5 and 6 respectively. For spectral analysis, HRV and HR segment scored 81 and 75% respectively. ST, QT, PRQ have 75, 62 and 68% respectively. CONCLUSIONS: The results obtained demonstrate that HR, HRV, PRQ, QT and ST segments under a normal, healthy condition are affected by glucose and should be considered for modelling a system to achieve the possibility of non-invasive blood glucose measurement with ECG.

Long-term blood glucose monitoring with implanted telemetry device in conscious and stress-free cynomolgus monkeys.

AIMS: Continuous blood glucose monitoring, especially long-term and remote, in diabetic patients or research is very challenging. Nonhuman primate (NHP) is an excellent model for metabolic research, because NHPs can naturally develop Type 2 diabetes mellitus (T2DM) similarly to humans. This study was to investigate blood glucose changes in conscious, moving-free cynomolgus monkeys (Macaca fascicularis) during circadian, meal, stress and drug exposure. MATERIALS AND METHODS: Blood glucose, body temperature and physical activities were continuously and simultaneously recorded by implanted HD-XG telemetry device for up to 10 weeks. RESULTS AND DISCUSSION: Blood glucose circadian changes in normoglycemic monkeys significantly differed from that in diabetic animals. Postprandial glucose increase was more obvious after afternoon feeding. Moving a monkey from its housing cage to monkey chair increased blood glucose by 30% in both normoglycemic and diabetic monkeys. Such increase in blood glucose declined to the pre-procedure level in 30 min in normoglycemic animals and >2 h in diabetic monkeys. Oral gavage procedure alone caused hyperglycemia in both normoglycemic and diabetic monkeys. Intravenous injection with the stress hormones, angiotensin II (2 µg/kg) or norepinephrine (0.4 µg/kg), also increased blood glucose level by 30%. The glucose levels measured by the telemetry system correlated significantly well with glucometer readings during glucose tolerance tests (ivGTT or oGTT), insulin tolerance test (ITT), graded glucose infusion (GGI) and clamp. CONCLUSION: Our data demonstrate that the real-time telemetry method is reliable for monitoring blood glucose remotely and continuously in conscious, stress-free, and moving-free NHPs with the advantages highly valuable to diabetes research and drug discovery.

A Glucose Sensing System Based on Transmission Measurements at Millimetre Waves using Micro strip Patch Antennas.

We present a sensing system operating at millimetre (mm) waves in transmission mode that can measure glucose level changes based on the complex permittivity changes across the signal path. The permittivity of a sample can change significantly as the concentration of one of its substances varies: for example, blood permittivity depends on the blood glucose levels. The proposed sensing system uses two facing microstrip patch antennas operating at 60 GHz, which are placed across interrogated samples. The measured transmission coefficient depends on the permittivity change along the signal path, which can be correlated to the change in concentration of a substance. Along with theoretical estimations, we experimentally demonstrate the sensing performance of the system using controlled laboratory samples, such as water-based glucose-loaded liquid samples. We also present results of successful glucose spike detection in humans during an in-vivo Intravenous Glucose Tolerance Test (IVGTT). The system could eventually be developed into a non-invasive glucose monitor for continuous monitoring of glucose levels for people living with diabetes, as it can detect as small as 1.33 mmol/l (0.025 wt%) glucose concentrations in the controlled water-based samples satisfactorily, which is well below the typical human glucose levels of 4 mmol/l.

Association of cigarette and water-pipe smoking with increased visceral adiposity, glycemic intolerance and hematological derangement in Iraqi healthy smokers

Abstract The present study aims to investigate the impacts of cigarette smoking (CS) and water-pipe smoking (WPS) on the visceral adiposity index (VAI), hematological characteristics, and glycemic tolerance in Iraqi healthy smokers. A total of 528 healthy males from different locations of Baghdad city were allocated to three groups; nonsmokers (176), cigarette smokers (178), and WP smokers (174). Baseline characteristics, anthropometric and hematological markers and were reported. Glycemic control was evaluated using the glucose tolerance test. The evidence of elevated VAI, disrupted hematological markers, and impaired glucose tolerance was significantly (P<0.001) different compared with non-smokers and related to the duration of smoking. The impacts of WPS seem to be significantly greater than CS in certain parameters (hemoglobin, hematocrit, methemoglobin, and 2-hour glucose tolerance values). In conclusion, CS and WPS negatively impacted body fat distribution, glucose tolerance, and hematological markers. There is a positive association between the rate of smoking and obesity, glycemic intolerance in both groups

AKA-Glucose: a program for kinetic and epidemiological analysis of frequently sampled intravenous glucose tolerance test data using database technology.

BACKGROUND: The Bergman Minimal Model enables estimation of two key indices of glucose/ insulin dynamics: glucose effectiveness and insulin sensitivity. METHODS AND RESULTS: In this paper we describe AKA-Glucose, a program that combines MINMOD Millennium (minimal model analysis software) with relational database technologies. AKA-Glucose enables the fitting of individual frequently sampled intravenous glucose tolerance test (FSIGT) data sets to the Minimal Model and the secure storage in a dedicated database (and retrieval from) of thousands of individual subjects' demographic data, their individual FSIGT data, and each subject's parameters and indices derived from minimal model analysis. AKA-Glucose also enables the population analysis of various strata or subpopulations within the database. AKA-Glucose has all of the capabilities of MINMOD Millennium, provides Minimal Model parameter estimates that are concordant with estimates from previous MINMOD software, and allows importation of data files from earlier versions of the MINMOD software. CONCLUSIONS: By combining FSIGT data fitting, population analysis, and relational database technologies, AKA-Glucose is the first minimal model software designed specifically for researchers confronted with minimal model and epidemiological analysis of large numbers of either human or animal FSIGT data sets.

Challenges of implementing point-of-care testing (POCT) glucose meters in a pediatric acute care setting.

OBJECTIVES: To investigate factors contributing to analytical bias in POCT glucose values generated by the NICU versus the core laboratory. METHODS: The LifeScan Flexx hospital system glucose meters (SureStep) were used in precision and comparison studies between the NICU and laboratory (ABL715 and Vitros 950). RESULTS: Analysis of 40 neonatal blood samples revealed a positive bias between the NICU glucose meters versus either the laboratory glucose meter or instrument (mean difference of 0.28 and 0.21 mmol/L, respectively). Linear regression analysis (R2 = 0.0584) of the difference in glucose results versus time elapsed between measurements indicated that the bias observed between the NICU and laboratory glucose meters was not due to in vitro glycolysis for samples transported on ice. Further analysis indicated that the bias appeared to be mostly operator driven, with different NICU operators exhibiting different mean biases. Increasing the amount of blood applied to the SureStep Pro test strip (e.g., 60 vs. 20 microL), led to higher values for glucose concentration for the same blood. Nearly 50% of all glucose values reported for the NICU were obtained by the SureStep Flexx glucose meters in a 3-month period following the introduction of POCT, yet the number of laboratory-reported glucose results for the same period increased by 21% as compared to the previous year. CONCLUSIONS: Operator error appears to be a source of bias present between the NICU and laboratory, and despite glucose meter utilization in the NICU, the number of glucose measurements by the central laboratory increased after POCT introduction.

Noninvasive glucose measurement by monitoring of scattering coefficient during oral glucose tolerance tests. Non-Invasive Task Force.

BACKGROUND: Continuous glucose monitoring by means of optical glucose sensors would allow patients with diabetes to check their metabolic control to their convenience. In an earlier study, we showed that noninvasive glucose monitoring is feasible for rapid changes in blood glucose by means of measuring the scattering coefficient of human skin. In this study, we investigated whether also slower changes in blood glucose, this time induced by an oral glucose load, can also be monitored by this approach. METHODS: Five healthy subjects and 13 patients with type 2 diabetes have been given a 75-g oral glucose load. Portable noninvasive systems were used to measure the skin tissue scattering coefficient. For this purpose, two optical sensor heads were attached directly to the skin of each volunteer. Light was applied to the skin and the reflected light intensity was registered. RESULTS: In 8 of 10 measurements, correlation of changes in scattering coefficient with changes in glycemia was acceptable. In 19 of 26 measurements (73%) of patients with type 2 diabetes the observed changes in the scattering coefficient also correlated in acceptable manner. The accordance between the simultaneous measurements of the two sensor heads was acceptable in 13 of 18 volunteers and patients studied. There were virtually no differences in the quality of the measurements between healthy volunteers and patients with diabetes. CONCLUSIONS: This study shows that also slow changes in blood glucose induced by an oral glucose load can be monitored by registration of scattering coefficient changes. It remains to be elucidated why this has not been possible in all experiments.

Predictive value of HemoCue capillary whole blood glucose measurements in pregnancy.

OBJECTIVE: We determined the ability of capillary whole blood glucose concentrations to predict venous plasma and whole blood glucose levels. METHODS: During a standard oral glucose tolerance test in 29 pregnant women, paired capillary and venous blood samples were collected for analysis of glucose concentrations by the HemoCue photometer and by central laboratory methods. RESULTS: Glucose concentrations determined serially in a single blood sample by the HemoCue method were highly reproducible, with a coefficient of variation of 2.3%. However, glucose levels in blood from two different fingersticks from the same patient varied on average by 3 mg/dL, with a maximum difference of 14 mg/dL. Although capillary whole blood glucose results obtained by the HemoCue method correlated well with venous plasma or whole blood glucose measurements (r = 0.98 and r = 0.97, respectively) over the range investigated (60-250 mg/dL), individual capillary whole blood glucose measurements were only a fair predictor of venous values, with 95% of measured venous levels within +/- 26 mg/dL and +/- 20 mg/dL for concentrations predicted for plasma and whole blood, respectively. CONCLUSION: Sampling factors rather than measurement accuracy limit the ability of capillary whole blood glucose measurements to predict venous concentrations.

[Use of an automatic blood glucose measurement system for the assessment of insulin resistance during the oral glucose tolerance test]. / Utilizzazione di un sistema di controllo automatico della glicemia per la valutazione della insulino-resistenza durante OGTT.

An automatic glycemic control system (Beta-like, Esaote) was used to calculate the insulin area (IA) required to keep glycemia within the normal range during OGTT (using NDDG criteria). IA was calculated by adding total endogenous insulin to insulin infused by the Betalike system (Actrapid HM, Novo). During the test, glycemia was obliged to follow a mean normal curve using an insulin infusion according to a special algorithm which automatically adapted to individual parameter variations during the different stages of OGTT. Fourteen blood samples were collected to assay metabolites (glucose, NEFA, lactate and alanine) and hormones (insulin, C peptide, glucagon). Data on insulinemia and glycemia were used to calculate the respective areas under the total and incremental curve (IA expressed in UL-1 min-1 and GA expressed in mM.L-1.min-1); an insulin resistance index was then calculated (total and incremental) using the following formula: IA/(normal GA/patient GA). This test allows us: a) to evaluate the insulin secretory response to a standard glycemic stimulus represented by a glycemic curve within the normal range; b) to calculate the quantity of insulin necessary to maintain the glycemic curve within the normal range; c) to evaluate the body's total insulin resistance according to an index calculated on the basis of the insulin area required; d) to compare the calculated insulin resistance index with NEFA and glucagon data obtained during the test; e) to identify the exact evolution of these events over time during OGTT.

Evaluation of a simplified intravenous glucose tolerance test and a reflectance glucose meter for use in cats.

A simplified intravenous glucose tolerance test has been developed for use in domestic cats and the results compared with those obtained using the standard test. The simplified test used two cephalic catheters, implanted in unsedated, unanaesthetised cats three hours before the test. Blood samples were collected before and after intravenous administration of glucose (0.5 g/kg bodyweight). Blood glucose concentration was measured with a reflectance glucose meter and an automated chemistry analyser. There were no significant differences between the results derived from the two tests. Because the simplified glucose tolerance test is easier to perform, requires no anaesthesia, uses only cephalic catheters and can be done on an outpatient basis, it is more cost effective and more clinically applicable. There were no significant differences between the results of glucose measurements with the two machines and the simplified glucose tolerance test can therefore be carried out with the reflectance glucose meter.

Oral glucose tolerance test--can the reflectance meter replace laboratory-based methods?

Sixteen national servicemen detected to have glycosuria on routine medical examination were subjected to 3 successive oral glucose tolerance tests. Capillary blood glucose was measured by reflectance meter in the first test (oGTT1), venous whole blood glucose by Beckman Synchron CX3 Analyser in the second (oGTT2) and by both methods in the third (oGTT3). In oGTT1, 1 subject was classified as diabetic and 15 as Impaired Glucose Tolerance (IGT). In oGTT3, using capillary blood glucose, 1 was diabetic, 8 IGT and 7 normal. Using venous whole blood, in oGTT2, 1 was diabetic, 3 IGT and 12 normal as compared to 1 diabetic, 4 IGT and 11 normal in oGTT3. There is considerable variation in classification as a result of using capillary blood glucose measured by reflectance meter as compared to the laboratory-based method. Capillary blood glucose measurement for oral glucose tolerance test cannot be recommended.

Serum fructosamine concentrations in Singapore pregnant women.

Serum fructosamine levels in women at pregnancy (28 weeks' gestation) were determined. The women (n = 99) also participated in an oral glucose tolerance test (OGTT) with a 75g liquid glucose load, to determine their glucose tolerance. At 32 weeks' gestation, seventy-nine of them repeated the oral glucose tolerance test and fructosamine measurement. Results showed that fructosamine levels in pregnant women with normal glucose tolerance (2.20 +/- 0.19 mmol/l, n = 76), were not statistically different from those with glucose intolerance (gestational diabetes: 2.19 +/- 0.22 mmol/l, n = 23) at 28 weeks' and also 32 weeks' gestation. However, serum fructosamine levels in pregnant women were lower than those in non-pregnant subjects. Serum fructosamine measurement is not a sufficiently sensitive test for diagnosis of gestational diabetes.

Diabetes en urgencias: evaluación del control y tratamientos instaurados / Diabetes in emergency services: evaluation of monitoring and installed treatments

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[Accuracy of a continuous glucose monitoring system in detection of blood glucose during oral glucose tolerance test].

OBJECTIVE: To evaluate the accuracy of continuous glucose monitoring system (CGMS) during oral glucose tolerance test (OGTT) in the detection of blood glucose changes in glucose stress condition. METHODS: Forty-nine out-patients with fasting plasma glucose of 3.9-11.0 mmol/L underwent continuous blood glucose monitoring using CGMS for 3 days, and OGTT was conducted on the third day. The venous blood glucose was measured at 0, 30, 60, 90, and 120 min after oral glucose intake, and the accuracy of CGMS during OGTT was evaluated. RESULTS: The correlation indices between CGMS values and the venous blood glucose values during the entire OGTT and in phases of stable, rapidly rising and falling glucose levels were 0.928, 0.901, 0.924 and 0.902, respectively (P<0.001). Clarke error-grid analysis showed that more than 95% of the measured results fell into the A and B zones. CONCLUSION: CGMS values show good consistency with venous blood glucose values measured during OGTT. CGMS is accurate in detection of rapidly changing blood glucose during OGTT.