Urine Glucose Measurements Research Articles

Nano-Materials-Based Printed Glucose Sensor for Use in Incontinence Products for Health-Care Applications

Our recent development of a wireless humidity sensor system embedded in incontinence products enables new sensor applications to diagnose and supervise geriatric diseases (i.e., age-related diabetes mellitus type II). The measurement of glucose in urine, so-called glucosuria, is an early indicator for an incipient diabetes mellitus disease, whose symptoms are often age-related but misjudged. In this paper, an incontinence glucose sensor is printed with biocompatible ink and Prussian blue as an electron mediator on foil and functionalized with immobilized glucose oxidase. Inkjet printing of multiple layers of Nafion prevents large interference substances from diffusing into the measuring electrode and allows precise adjustment of the linear working range, which is significantly different from blood glucose measurement. Performance tests show the potential to detect minimum glucose values and store the sensor over a prolonged period at room temperature. The printed glucose sensor can be embedded into the absorber material of incontinence products, where capillary forces transport the urine analyte to the detection area. An attached readout module with an integrated potentiostat measures the glucose concentration in urine, which is transmitted wirelessly with incontinence events and stored in a cloud service for further analysis by medical staff and care workers.

Spurious HbA1c results in patients with diabetes treated with dapsone.

SummaryMeasurement of glycated haemoglobin (HbA1c) has been utilised in assessing long-term control of blood glucose in patients with diabetes, as well as diagnosing diabetes and identifying patients at increased risk of developing diabetes in the future. HbA1c reflects the level of blood glucose to which the erythrocyte has been exposed during its lifespan, and there are a number of clinical situations affecting the erythrocyte life span in which HbA1c values may be spuriously high or low and therefore not reflective of the true level of glucose control. In the present case series, we describe the particulars of three patients with diabetes who had spuriously low HbA1c levels as a result of dapsone usage. Furthermore, we discuss the limitations of HbA1c testing and the mechanisms by which it may be affected by dapsone in particular.Learning points:Various conditions and medications can result in falsely low HbA1c.Dapsone can lead to falsely low HbA1c by inducing haemolysis and by forming methaemoglobin.Capillary glucose measurement, urine glucose measurements and fructosamine levels should be used as alternatives to HbA1c for monitoring glycaemic control if it was falsely low or high.

A feasible image-based colorimetric assay using a smartphone RGB camera for point-of-care monitoring of diabetes

Urinary glucose determination using a glucose test strip is simple and convenient in daily self-monitoring of diabetes. However, diabetic patients exhibit acquired impaired color vision (ICV), which results in the inability to discriminate between hues. Even with the assistance of a color chart, it is still not easy for these patients to read the urinary glucose results with the naked eye. In this study, a smartphone camera using an image-based colorimetric detection method was successfully developed for quantitative analysis of urine glucose. A horseradish peroxidase-hydrogen peroxide-3,3′5,5′-tetramethylbenzidine (HRP–H2O2–TMB) system was optimized for a reliable and gradual color fading process via a glucose oxidase (GOD) catalyzed oxidation reaction. The color changes of the peroxidase-H2O2 enzymatic reactions in the 96-well microplate were captured by a smartphone RGB camera with subsequent detection of red, green, and blue (RGB) intensities decreasing at each image pixel. The highly quantitative relationships between the glucose concentrations and the color characteristic values of the blue channel of the captured images were successfully established. The high accuracy of this method was demonstrated in urine glucose measurements with a linear response over the 0.039 mg mL−1 to 10.000 mg mL−1 glucose concentration range and a 0.009 mg mL−1 detection limit. The method has great potential as a point-of-need platform for diabetic patients with defective color vision and features high accuracy and low cost.

Semiquantitative glucose measurements in urine samples and urine soaked cat litter

Semiquantitative urine glucose measurements are a proposed alternative for the treatment surveillance of unmanageable diabetic cats. The primary objectives of this study were to determine the accuracy of 5 commercially available dipsticks, to re-evaluate a technique for detecting glucosuria in urine-soaked "clumping" type of cat litter described by Schaer and to validate a cat toilet with a sieve bottom. A total of 93 urine samples were analysed using 5 different urine dipsticks. The correlation with a laboratory reference method and the diagnostic accuracy to diagnose pathological glucosuria > 1.48 mmol/l and urinary glucose concentrations ≥ 13.9 mmol/l (therapeutically important cut-off) were determined. Furthermore, the viability of 10 types of cat litter, a cat toilet with sieve bottom, 2 disinfectants, 2 cleaning agents and 2 cat litter deodorants were tested. The correlations of the dipstick results with the reference method were moderate (rSP = 0.633) to good (rSP = 0.846). The sensitivities and specificities to diagnose pathological glucosuria were 0.7-1 and 0.94-1, respectively. Urine glucose concentrations ≥ 13.9 mmol/l were detected with sensitivities of 0.65-1 and specificities of 0.97-1. Four cat litters, one dipstick and a disinfectant containing hydrogen peroxide caused false-positive colour reactions. Depending on the dipsticks and litter used, the measurements from soaked cat litter reduced the urine glucose concentrations by a median of 70-77 %. Pouring the probes into the cat toilet and subsequent measurements from the collecting tank did not falsify the results. Not all urine dipsticks are suitable to monitor insulin therapy in diabetic cats. False positive colour reactions are possible when using dipsticks with high analytical sensitivities, some cat litters and oxidizing disinfectants. Measurements from the collecting tank of the cat toilet are superior to measurements using soaked clumping type of cat litter.

Fabrication of Repeatedly Usable Pt-Electrode Chip Coated With Solidified Glucose Oxidase and Ascorbate Oxidase for the Quantification of Glucose in Urine

A repeated usable electrode sensor for the measurement of glucose in urine has been developed. For improvement of the selectivity in measuring glucose in urine, we fabricated the Pt electrode coated with multilayered composite of glucose oxidase (GOX) and ascorbate oxidase (AOX). This simple layer structure could deliver more electrons from glucose oxidation without interference from ascorbic acids by first oxidizing the ascorbic acids present in urine. Results showed that our newly developed Pt electrode is capable of quantifying the concentrations of glucose in urine in the range between 0 and 1000 mg/dL, as well as maintaining its detection stability during 200 times of repeated measurements. This repeatable use of the sensor is attributable to the solidified structure of AOX and GOX layer.

Basal glucosuria in cats.

Objective of this study was to demonstrate the ubiquitous presence of glucose in urine of euglycemic cats by a highly sensitive glucose assay. The local electronic database was searched for results of quantitative urine glucose measurements in cats. A total of 325 feline urine glucose measurements were identified, of which 303 (93%) had been submitted by one of the co‐authors working in a near‐by small animal practice. After the exclusion of patients with kidney disease (n = 60), hyperthyroidism (n = 15), diabetes mellitus (n = 11), multiple diseases (n = 9) or steroid treatment (n = 3), as well as serial measurements (n = 87) and outliers (n = 8), the final study population consisted of 132 cats. Urine creatinine concentration was unavailable in five patients. Whereas all but one cat had glucose concentrations above the detection limit of the assay (0.11 mmol/L, Gluco‐quant Enzyme Kit/Roche Diagnostics), no positive glucose dipstick test result (Combur 9‐Test, Roche Diagnostics) was observed. The median (range) of urinary glucose concentration and the glucose‐to‐creatinine ratio (UGCR) was 0.389 (<0.11–1.665) mmol/L and 0.0258 (0.007–0.517) respectively. The UGCR was not affected by age, gender, breed or leukocyturia, whereas cats with hematuria had slightly higher values. Data show that so‐called “basal glucosuria” is present in the majority of cats and by no means diagnostic for diabetes mellitus or renal glucosuria. This has to be considered when using bio‐analytical methods with a low limit of quantification.

Elevated fructosamine concentrations caused by IgA paraproteinemia in two dogs

An 8-year-old male Austrian Pinscher and a 14-year-old male Golden Retriever were presented for evaluation due to unexplainable high fructosamine values despite euglycemia and epistaxis in combination with polydipsia/polyuria, respectively. Blood analysis revealed severe hyperglobulinemia, hypoalbuminemia and markedly elevated fructosamine concentrations in both dogs. Multiple myeloma with IgA-monoclonal gammopathy was diagnosed by serum and urine electrophoresis including immunodetection with an anti-dog IgA antibody and bone marrow aspirations. Diabetes mellitus was excluded by repeated plasma and urine glucose measurements. Fructosamine values were positively correlated with globulin, but negatively correlated with albumin concentrations. These cases suggest that, as in human patients, monoclonal IgA gammopathy should be considered as a possible differential diagnosis for dogs with high fructosamine concentrations.

What should we measure in the diabetic patient and how does this respond to therapy?

Diabetes is characterized by hyperglycaemia and by the development of complications. The criteria for diagnosis have been revised and published by the World Health Organization (WHO). In a symptomatic patient, a random plasma glucose concentration of ≥11.1 mmol l−1 is diagnostic. For asymptomatic patients, two diagnostic tests are required. A fasting glucose level ≥7 mmol l−1 confirms the diagnosis (providing this is supported by a second diagnostic test). The 75 g oral glucose tolerance test, as recommended by the WHO, is used for diagnosis in borderline cases or for academic studies. A plasma glucose concentration ≥11.1 mmol l−1 at 2 h following oral glucose confirms the diagnosis (Table 1). Table 1 Values for diagnosis of diabetes mellitus and other categories of hyperglycaemia.

Index of Suspicion

Index of Suspicion

Development of a bio-thermochip and its application for the detection of glucose in urine

A portable and inexpensive biothermistor system (bio-thermochip) has been developed by constructing the enzyme immobilization support around the bead thermistor. The support enhances the enzyme loading and heat production around the thermistor. Glucose oxidase (GOD) and bovine serum albumin (BSA) were immobilized around the two bead thermistors, respectively. The temperature difference between the GOD immobilized thermistor and the BSA immobilized reference thermistor was measured in an insulated cell, allowing detection of small temperature changes. A linear calibration graph was obtained for glucose concentrations in the range of 1 to 4 mM. The response of the bio-thermochip was about a factor of two larger than the thermistor without enzyme support. The response was maximum at pH 6 and independent of the presence of ascorbic acid and other reducing components in urine. This system is suitable for the measurement of glucose in urine.

Sucrose urinary excretion in the rat measured using a simple assay: a model of gastroduodenal permeability.

To develop a non-invasive animal model suitable for studies of altered gastroduodenal (GD) permeability, which is suggested to indicate GD damage; to validate a low cost and convenient assay for sucrose in urine, a permeability marker of GD. Control (n = 87) and treated male Sprague-Dawley rats were dosed orally with 1 g of sucrose. Urinary excretion of the sucrose (0-8 h) was measured indirectly by cleavage to glucose and subsequent measurement of glucose in urine using a calorimetric assay. Treated rats were administered single oral doses of 10 and 20 mg/kg indomethacin, or 42 mg/kg aspirin alone or with 0.5 mL 50% ethanol (n = 7 in each group). The assay was linear within the examined range of 10-100 ug/mL sucrose. The inter and intraday variations were 7.63% and 6.89%, respectively. The urinary excretion of sucrose was complete in 8 h. In control rats the urinary excretion of sucrose exhibited a left skewed frequency distribution curve with a mean of 0.6 +/- 0.14% of the dose excreted. All treatment, with the exception of 10 mg/kg indomethacin significantly increased the GD permeability. The GD effect was found to be dose dependent and parallels those reported for humans. The rat is a suitable model for studies of GD permeability. Combined use of sucrose and 51Cr-EDTA, a marker of intestinal permeability, allows for non-invasive examination of abnormalities of the entire gut. The sucrose assay is convenient and cost effective. The rat model may be useful in the preclinical screening of NSAID formulations and also in the detection of other GI abnormalities.

Effect of Long-Term Monitoring of Glycosylated Hemoglobin Levels in Insulin-Dependent Diabetes Mellitus

The value of routine measurements of glycosylated hemoglobin (hemoglobin A1c) in the care of patients with diabetes mellitus is uncertain. We undertook this study to determine whether knowledge of hemoglobin A1c values would result in improved metabolic control in a group of patients with insulin-dependent diabetes mellitus (IDDM). We randomly assigned 240 patients with IDDM to one of two groups that were comparable in age, sex, duration of diabetes, and initial hemoglobin A1c levels. The patients were followed for a year, and the hemoglobin A1c concentration was measured at three-month intervals. The hemoglobin A1c values were used in assessing glycemic control and modifying therapy in one of the two groups. In the other, care givers were not aware of the hemoglobin A1c levels and relied on blood or urine glucose measurements to monitor treatment. Among the 222 patients still being followed after one year, the mean hemoglobin A1c value decreased significantly--from 10.1 to 9.5 percent (P less than 0.005)--in the group whose hemoglobin A1c level was monitored (n = 115), whereas the initial and one-year values in the control group (n = 107) were 10.0 and 10.1 percent, respectively. The proportion of patients with poor control, defined as those having a hemoglobin A1c value above 10.0 percent, decreased from 46 to 30 percent (P less than 0.01) in the group whose hemoglobin A1c level was monitored but did not change significantly (45 to 50 percent) in the control group. The patients in the group whose hemoglobin A1c level was monitored were seen and their insulin regimens changed more often, but they were hospitalized for acute care of their diabetes less often than those in the control group. A similar decrease in hemoglobin A1c values occurred in the control group in the following year, when their care givers knew their hemoglobin A1c values. Regular measurements of hemoglobin A1c lead to changes in diabetes treatment and improvement of metabolic control, indicated by a lowering of hemoglobin A1c values.

Glucose Control and Renal and Retinal Complications of Diabetes Mellitus-Reply

ABSTRACT In Reply.— Dr Gwinup should be aware that the urine glucose measurements of the 1950s and the 1960s were shown to be of little value in the 1970s and the 1980s. Teenagers were smarter than we physicians in learning to exercise, avoid sweets, get all of the insulin in, etc, on urine collection days. They could affect the results as they wished. In addition, numerous investigators showed that the kidney threshold for glucose varied from person to person, and even from one time of day to another time of day for the same individual. Thus, our article in JAMA represents the first study with more than 1 or 2 years of data in which a reliable objective measurement, the glycohemoglobin, was used to evaluate glucose control longitudinally.Dr Gwinup should also be aware that the microalbumin measurements used in the article were shown in the 1980s to be an

Blood or Urine Glucose-Based Insulin Therapy and Control of Glycemia: Computer-Simulation Study

Adjustment algorithms for conventional insulin therapy must be tested for safety and efficacy before clinical implementation. We did this by computer simulation. Accordingly, a computer simulator of human intermediary metabolism created 10 randomly chosen diabetic subjects for study. All were well defined with respect to compliance (i.e., medication and diet) and life-style (i.e., physical and emotional stress). Insulin-adjustment algorithms that were tested calculated daily insulin dosages for these computer-simulated patients based on either blood or urine glucose concentrations self-measured 4 times/day before breakfast, lunch, dinner, and bedtime snack. The twofold purpose of the simulation study was to determine the ability of the adjustment algorithms to improve initially poor metabolic control and to compare the outcomes when either blood or urine glucose measurements were the basis on which glycemic control was implemented. A significant improvement in metabolic control could be achieved with either blood or urine glucose measurements as input to the algorithms. Detailed comparisons between blood and urine glucose-based treatments showed no significant advantage of blood glucose-based algorithms at breakfast (122 +/- 21 vs. 131 +/- 16 mg/dl) and dinner (117 +/- 27 vs. 130 +/- 23 mg/dl), whereas mean glycemia at lunch (122 +/- 24 vs. 164 +/- 21 mg/dl) and bedtime (117 +/- 25 vs. 150 +/- 21 mg/dl) after 120 days of simulation did differ significantly (P less than 0.01). Hypoglycemia was not provoked by either treatment. Total daily insulin doses evolved by blood glucose-based algorithms were significantly (P less than 0.05) higher than the doses used by urine glucose-based algorithms (53 vs. 47 U).(ABSTRACT TRUNCATED AT 250 WORDS)

Single and double voided urine testing: A comparison with blood glucose monitoring in insulin‐dependent diabetics

AbstractIn order to assess the degree of correlation between glycosuria in both single and double voided urine specimens and simultaneous capillary blood glucose measurements, an outpatient study on nine adult insulin‐dependent diabetics collected 778 paired blood and urine measurements. Although low blood glucose readings were usually associated with negative glycosuria, there was considerable variation both within the group and individual patients.Additional data was collected during the routine care of 83 diabetic children at 2 educational holidays. Paired urine and blood measurements were obtained on 1,236 occasions, on 362 of which double voiding was attempted. These data also showed considerable scatter and poor overall correlation between single voided urine and capillary blood glucose, and no improvement with double voiding.In the adults, the correlation was not affected by analysis of morning versus evening results, by once or twice‐daily insulin regimens, or by the method used for urine testing.The conclusions are: Urine glucose measurements are poor predictors of prevailing blood glucose levels. Double voiding of urine for urinalysis appears to have no additional advantages over single voiding.

Urine Glucose Tests for Diabetic Patients with Impaired Vision

A colorimetric test procedure called Mega-Diastix is described for detection and measurement of glucose in urine. The test is designed for use by diabetic patients with imparied vision. Data establishing the performance capabilities of this rapid, convenient test are presented. As an internal standard, the recommended procedure utilizes effervescent control tablets for preparation of simulated urine. Also described is a touch fermentation test for detection of urinary glucose by totally blind patients. Data are given that demonstrate the accuracy and ease of performance of this test, which entails a rapid yeast fermentation. An internal standard is also incorporated into the procedure for this test.

Glucose oxidase chemiluminescence measurement of glucose in urine compared with the hexokinase method.

Glucose oxidase chemiluminescence measurement of glucose in urine compared with the hexokinase method.

History of the Measurement of Glucose in Urine: A Cautionary Tale

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An antomated method for the quantitative assessment of low concentrations of glucose in urine.

In view of the recent work by Schersten and Fritz (1967), which indicates that the utilization of small amounts of glucose in urine by actively respiring bacteria can be used as an index of urinary tract infection, there is a need for a simple, sensitive test which detects very low concentration of urine glucose and can be applied in the analysis of large numbers of specimens. This paper describes the adaptation of a routine blood glucose autoanalyser method to the measurement of glucose in urine.

Enzymatic Determinations of Glucose

Publisher Summary This chapter highlights that glucose is important in the metabolism of most cells—animal, plant, and microbe—and a number of enzymes have been identified which catalyze the reactions of glucose. It discusses that enzymatic methods have a number of theoretical advantages, and therefore, it is quite logical that much attention has been devoted to the subject of enzymatic determinations of glucose. In all instances, the theoretical advantages do not necessarily apply in the defined procedures. Early qualitative and quantitative tests in which yeast was employed for either the identification or measurement of glucose might be considered to have an enzymatic basis as the desired actions were accomplished by means of the enzymatic processes in living yeast cells. This chapter describes the history and properties of glucose oxidase. It presents an account of the utilization of glucose oxidase for the measurement of glucose in urine and blood, and for other test situations that may be of interest in clinical chemistry.