Assessment of five portable blood glucose meters, a point-of-care analyzer, and color test strips for measuring blood glucose concentration in dogs

Impact on result interpretation of correct and incorrect selection of veterinary glucometer canine and feline settings

Veterinary glucometers should be correctly coded for the patient species; however, coding errors occur in clinical settings and the impact of such errors has not been characterized. We compared glucose concentrations in 127 canine and 37 feline samples using both canine and feline settings on a veterinary glucometer (AlphaTrak; Zoetis). All samples were measured first on the canine setting and then measured using the feline setting. Glucose concentration was also measured using a central laboratory biochemical analyzer (Cobas c311; Roche). Three data comparisons for each species were investigated: incorrectly coded glucometer vs. correctly coded glucometer, correctly coded glucometer vs. Cobas c311, and incorrectly coded glucometer vs. Cobas c311. For each comparison, the following analyses were conducted: Spearman rank correlation coefficient, Bland-Altman difference plot analysis, mountain plot analysis, and Deming regression. For clinical context, Clarke error grids were constructed. There was high positive correlation for all comparisons with both species. For all comparisons, mean difference was low (-0.7 to 0.5 mmol/L for canine samples, 1.0-2.0 mmol/L for feline samples). Incorrect glucometer coding resulted in proportional bias for canine samples and positive constant bias for feline samples, and individual differences could be large (-4.44 mmol/L for one dog, 6.16 mmol/L for one cat). Although the glucometer should be used per the manufacturer's recommendation, coding errors are unlikely to have severe adverse clinical consequences for most patients based on error grid analysis.

Evaluation of Three Human-Use Glucometers for Blood Glucose Measurement in Dogs

BACKGROUND

Glucometers or portable sensors are used to quickly measure blood glucose at low cost. They are used in veterinary practice and by guardians to monitor diseases that require, as in diabetes mellitus. However, not all commercially available glucometers (human and veterinary) are suitable for this purpose. Hypotheses/Objectives. The objective was to evaluate the analytical and clinical precision of three human-use portable glucometers. Animals. This study evaluated 115 samples in three glycemic ranges (hypoglycemia, normoglycemia, and hyperglycemia) from 82 dogs recruited from veterinary services.

METHODS

The portable glucometers are the FreeStyle Freedom Lite®, FreeStyle Optium Neo®, and On Call Plus® models. Glucometer results were compared with the enzymatic colorimetric glucose oxidase laboratory reference method. Using descriptive and comparative statistical analysis, there were correlations between these devices and the standard method, ISO 15197 : 2003 and ISO 15197 : 2013 standards, and error grid analysis.

RESULTS

Only the Freedom Lite® device observed a statistical difference when compared with the reference method. Despite the underestimated glucose concentrations assessed with humane devices, all three tested herein showed a positive coefficient. However, none of these achieved all ISO guidelines. Conclusion and Clinical Importance. Although there was wide use of portable humane devices for dog glucose measurements on routine, the results are generally inferior when compared to the reference method. The FreeStyle Optium Neo® glucometer obtained the best result and is therefore the best option among the glucometers evaluated; however, for the first attendance on veterinary routine, all three glucometers had a satisfactory glucose measurement until the reference method availability.

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.

Comparison of glucose concentrations in canine whole blood, plasma, and serum measured with a veterinary point-of-care glucometer

Previous studies have determined that, compared to whole blood, serum or plasma used in a portable blood glucometer (PBG) may provide more accurate results. We investigated the accuracy of a veterinary PBG (AlphaTRAK 2; Zoetis) for the measurement of glucose concentrations in serum, plasma, and whole blood compared to plasma glucose concentration measured by a biochemical analyzer. Blood samples from 53 client-owned dogs were collected. Lin concordance correlation coefficient (ρ_c) and Bland-Altman plots were used to determine correlation and agreement between the results obtained for the different sample types. Glucose concentration in whole blood measured by the veterinary PBG was more strongly correlated with the glucose concentration measured by the biochemical analyzer (ρ_c = 0.92) compared to plasma and serum glucose concentrations (ρ_c = 0.59 and 0.57, respectively). The mean differences between the glucose concentrations in whole blood, plasma, and serum measured by the veterinary PBG and the glucose concentration determined by the biochemical analyzer were 1.0, 6.3, and 6.7 mmol/L (18, 113, and 121 mg/dL), respectively. Our findings suggest that, when using this veterinary PBG, the accuracy of a glucose measurement obtained is higher when using whole blood compared to plasma or serum. Use of whole blood allows for more correct assessment and diagnosis, which are necessary for appropriate therapeutic intervention.

Comparison of glucose concentrations in serum, plasma, and blood measured by a point-of-care glucometer with serum glucose concentration measured by an automated biochemical analyzer for canine and feline blood samples

OBJECTIVE

To determine the correlation between glucose concentrations in serum, plasma, and blood measured by a point-of-care glucometer (POCG) and serum glucose concentration measured by an automated biochemical analyzer (ABA; gold standard).

SAMPLE

152 canine and 111 feline blood samples.

PROCEDURES

For each sample, the glucose concentration in serum, plasma, and blood was measured by a POCG and compared with the ABA-measured glucose concentration by means of the Lin concordance correlation coefficient. Results were summarized by species for all samples and subsets of samples with hyperglycemia (ABA-measured glucose concentration > 112 mg/dL for dogs and > 168 mg/dL for cats) and pronounced hyperglycemia (ABA-measured glucose concentration > 250 mg/dL for both species). The effect of PCV on correlations between POCG and ABA measurements was also assessed.

RESULTS

Hyperglycemia and pronounced hyperglycemia were identified in 69 and 36 canine samples and 44 and 29 feline samples, respectively. The POCG-measured glucose concentrations in serum, plasma, and blood were strongly and positively correlated with the gold standard concentration. The PCV was positively associated with the correlation between the POCG-measured blood glucose concentration and the gold standard concentration but was not associated with the correlations between the POCG-measured glucose concentrations in serum and plasma and the gold standard concentration.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated that POCG-measured glucose concentrations in serum, plasma, and blood were strongly correlated with the ABA-measured serum glucose concentration, even in hyperglycemic samples. Given the time and labor required to harvest serum or plasma from blood samples, we concluded that blood was the preferred sample type for use with this POCG.

Effect of site of sample collection and prandial state on blood glucose concentrations measured with a portable blood glucose meter in healthy dogs

OBJECTIVE

To compare glucose concentrations in peripheral venous and capillary blood samples collected from dogs before and after consumption of a meal and measured with a veterinary-specific portable blood glucose meter (PBGM).

ANIMALS

12 dogs (96 blood samples).

PROCEDURES

A veterinary-specific PBGM was used to measure blood glucose concentrations. Glucose concentrations in capillary blood samples obtained from the carpal pad, medial aspect of a pinna, and oral mucosa were compared with glucose concentrations in blood samples obtained from a lateral saphenous vein. Samples were collected after food was withheld for 12 hours and again 2 hours after consumption of a meal.

RESULTS

Location of capillary blood collection had a significant effect on glucose concentrations measured with the PBGM. Glucose concentration in capillary blood collected from the medial aspect of the pinna did not differ significantly from the glucose concentration in peripheral venous blood samples, whereas glucose concentrations in blood samples collected from the carpal pad and oral mucosa differed significantly from the glucose concentration in peripheral venous blood samples. There was no significant difference between preprandial and postprandial blood glucose concentrations.

CONCLUSIONS AND CLINICAL RELEVANCE

Glucose concentrations in capillary blood collected from the medial aspect of the pinna of dogs better reflected glucose concentrations in venous blood than concentrations measured in capillary blood collected from the carpal pad or oral mucosa.

Precision and accuracy of a point-of-care glucometer in horses and the effects of sample type

Point-of-care glucometry is used commonly in clinical and research settings; however, accuracy and precision of this method are concerns. The objectives of this study were to determine the accuracy of glucometry in adult horses and the precision of duplicate measurements. Blood samples were collected from 62 horses into one plain syringe, one EDTA tube and three fluoride oxalate (FO) tubes. Immediately after collection, glucose concentrations in whole blood were determined, in duplicate, by glucometry from the syringe (plain whole blood [WB] group), EDTA tube (EDTA group) and one FO tube (FO group). One FO sample was used to measure plasma glucose concentration by a laboratory chemistry analyser (LAB group) ≤1 h after collection. The third FO tube was used to measure plasma glucose concentration by glucometry after 3 h storage (FO3hr group). Adequate precision was present for all groups (coefficient of variation: 0.7-3.5%) except WB (5.5-9.4%). Between groups, correlations were significant (P < 0.05; except for WB-EDTA), varied with group comparison, and tended to be lowest for comparisons involving WB. Mean bias was lowest for WB-LAB and greatest for FO-LAB and FO3hr-LAB; however, the limits of agreement were ≥4.65 mmol/L for WB-LAB and ≤2.75 mmol/L for most other comparisons. For the glucometer used, performance was influenced by sample type: WB was unsuitable, while FO or EDTA samples resulted in adequate precision and accuracy, provided under-estimation of glucose concentrations is accounted for by using method-specific reference ranges. Glucometer performance and optimal sample type(s) should be determined prior to use in horses.

Engineering a simple lateral flow device for animal blood coagulation monitoring

Increasing numbers of animals are diagnosed with thromboembolism, requiring anticoagulation treatment to prevent thrombotic events. Frequent and periodic coagulation monitoring is critical to ensure treatment effectiveness and patient safety by limiting blood coagulation ability within the desired therapeutic range. Point-of-care diagnostics is an ideal candidate for frequent coagulation monitoring due to rapid test results and no need for laboratory setting. This article reports the first utilization of no-reaction lateral flow assay (nrLFA) device for simple and low-cost animal blood coagulation monitoring in resource-limited setting. The nrLFA device consists of sample pad, analytical membrane and wicking pad, without conjugate pad, reagent printing or membrane drying. Citrated and heparinized animal blood were utilized to mimic different blood coagulation abilities in vitro by adding reversal agents CaCl2 and protamine sulfate. The travel distance of red blood cells (RBCs) on the nrLFA after a pre-determined test time serves as endpoint marker. Upon adding 500 mM CaCl2 solution to citrated bovine, canine, rabbit and equine blood, the average travel distance decreases from 10.9 to 9.4 mm, 8.8 to 5.7 mm, 12.6 to 9 mm, and 15.3 to 11.3 mm, respectively. For heparinized bovine and rabbit blood, the average distance decreases from 14.5 to 11.4 mm and from 9.8 to 7.2 mm, respectively, when adding 300 mg/l protamine sulfate solution. The effect of hematocrit on RBC travel distance in the nrLFA was also investigated. The nrLFA device will potentially improve treatment efficiency, patient safety, quality of life, and satisfaction for both animal patients and their owners.

Obtaining accurate glucose measurements from wild animals under field conditions: comparing a hand held glucometer with a standard laboratory technique in grey seals

Glucose is an important metabolic fuel and circulating levels are tightly regulated in most mammals, but can drop when body fuel reserves become critically low. Glucose is mobilized rapidly from liver and muscle during stress in response to increased circulating cortisol. Blood glucose levels can thus be of value in conservation as an indicator of nutritional status and may be a useful, rapid assessment marker for acute or chronic stress. However, seals show unusual glucose regulation: circulating levels are high and insulin sensitivity is limited. Accurate blood glucose measurement is therefore vital to enable meaningful health and physiological assessments in captive, wild or rehabilitated seals and to explore its utility as a marker of conservation relevance in these animals. Point-of-care devices are simple, portable, relatively cheap and use less blood compared with traditional sampling approaches, making them useful in conservation-related monitoring. We investigated the accuracy of a hand-held glucometer for 'instant' field measurement of blood glucose, compared with blood drawing followed by laboratory testing, in wild grey seals (Halichoerus grypus), a species used as an indicator for Good Environmental Status in European waters. The glucometer showed high precision, but low accuracy, relative to laboratory measurements, and was least accurate at extreme values. It did not provide a reliable alternative to plasma analysis. Poor correlation between methods may be due to suboptimal field conditions, greater and more variable haematocrit, faster erythrocyte settling rate and/or lipaemia in seals. Glucometers must therefore be rigorously tested before use in new species and demographic groups. Sampling, processing and glucose determination methods have major implications for conclusions regarding glucose regulation, and health assessment in seals generally, which is important in species of conservation concern and in development of circulating glucose as a marker of stress or nutritional state for use in management and monitoring.

Glucose Detection and Concentration Estimation in Feline Urine Samples with the Bayer Multistix and Purina Glucotest

The Bayer Multistix are commonly used for detection and estimation of feline glucosuria by veterinarians and cat owners. A newer product, the Purina Glucotest, utilizes the same enzymatic technology for detection of glucose, but has been designed for home use as a litter additive that allows interpretation of glucosuria over an 8-h period. The objectives of this study were to assess the sensitivity, specificity, and accuracy of the Glucotest and Multistix, and to assess the 8-h color stability of the Glucotest. Overall, the Glucotest had greater sensitivity and specificity than the Multistix, and more accurately estimated urine glucose concentration if evaluated at least 30 min after exposure to urine. A significant lack of agreement between the results obtained immediately after exposure to urine vs after 30 min and 8 h contradicts the 8-h color stability claim, but the change in urine glucose concentration estimation over time resulted in improved test accuracy at the 30 and 480 min time points.

Home-monitoring of blood glucose in cats with diabetes mellitus: Evaluation over a 4-month period

Home-monitoring of blood glucose concentrations has recently been introduced to owners. The objectives of this study were to investigate the feasibility of home-monitoring of blood glucose in diabetic cats by owners, the problems encountered and to compare glucose concentrations at home with those measured in the hospital. Twelve of 15 cat owners were able to generate glucose curves over the study period of 4 months. Most problems were related to restraining the cat, generating negative pressure with the lancing device and producing a blood drop. In the majority of cases, these problems could be resolved during the study. Blood glucose concentrations in the clinic tended to be lower than at home; some of the differences were significant. No association between tolerance of the procedure and blood glucose concentrations measured at home was found. We, therefore, assume that the lower glucose levels in the hospital were caused by lack of food intake. In 38% of cases, treatment based on hospital curves would have been different from that based on home curves. Home-monitoring appears to be a valuable tool in the management of cats with diabetes mellitus. One of its major advantages is that it enables frequent generation of blood glucose curves, which is of particular importance in cats that are difficult to regulate.

Point-of-Care Glucose and Ketone Monitoring

Early and rapid identification of hypo- and hyperglycemia as well as ketosis is essential for the practicing veterinarian as these conditions can be life threatening and require emergent treatment. Point-of-care testing for both glucose and ketone is available for clinical use and it is important for the veterinarian to understand the limitations and potential sources of error with these tests. This article discusses the devices used to monitor blood glucose including portable blood glucose meters, point-of-care blood gas analyzers and continuous glucose monitoring systems. Ketone monitoring options discussed include the nitroprusside reagent test strips and the 3-β-hydroxybutyrate ketone meter.

Correlation between glucose concentrations in serum, plasma, and whole blood measured by a point-of-care glucometer and serum glucose concentration measured by an automated biochemical analyzer for canine and feline blood samples

OBJECTIVE

To investigate the correlation between glucose concentrations in serum, plasma, and whole blood measured by a point-of-care glucometer (POCG) and serum glucose concentration measured by a biochemical analyzer.

DESIGN

Prospective clinical study.

SAMPLES

96 blood samples from 80 dogs and 90 blood samples from 65 cats.

PROCEDURES

Serum, plasma, and whole blood were obtained from each blood sample. The glucose concentrations in serum, plasma, and whole blood measured by a POCG were compared with the serum glucose concentration measured by a biochemical analyzer by use of the Lin concordance correlation coefficient (ρc) and Bland-Altman plots.

RESULTS

For both canine and feline samples, glucose concentrations in serum and plasma measured by the POCG were more strongly correlated with the serum glucose concentration measured by the biochemical analyzer (ρc, 0.98 for both canine serum and plasma; ρc, 0.99 for both feline serum and plasma) than was that in whole blood (ρc, 0.62 for canine samples; ρc, 0.90 for feline samples). The mean difference between the glucose concentrations determined by the biochemical analyzer and the POCG in serum, plasma, and whole blood was 0.4, 0.3, and 31 mg/dL, respectively, for canine samples and 7, 6, and 32 mg/dL, respectively, for feline samples.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated that use of a POCG to measure glucose concentrations in serum or plasma may increase the accuracy and reliability of diagnostic and treatment decisions associated with glucose homeostasis disorders in dogs and cats.

Point-of-Care Blood Gases, Electrolytes, Chemistries, Hemoglobin, and Hematocrit Measurement in Venous Samples from Pet Rabbits

Point-of-care testing is an attractive option in rabbit medicine, because it permits rapid analysis of a panel of electrolytes, chemistries, blood gases, hemoglobin, and hematocrit, requiring only 65 μL of blood. The purpose of this study was to evaluate the performance of a portable clinical analyzer for measurement of pH, partial pressure of CO2, Na, chloride, potassium, blood urea nitrogen, glucose, hematocrit, and hemoglobin in healthy and diseased rabbits. Blood samples obtained from 30 pet rabbits were analyzed immediately after collection by the portable clinical analyzer (PCA) and immediately thereafter (time &lt;20 sec) by a reference analyzer. Bland-Altman plots and Passing-Bablok regression analysis were used to compare the results. Limits of agreement were wide for all the variables studied, with the exception of pH. Most variables presented significant proportional and/or constant bias. The current study provides sufficient evidence that the PCA presents reliability for pH, although its low agreement with a reference analyzer for the other variables does not support their interchangeability. Limits of agreement provided for each variable allow researchers to evaluate if the PCA is reliable enough for their scope. To the authors’ knowledge, the present is the first report evaluating a PCA in the rabbit.

ISO-based assessment of accuracy and precision of glucose meters in dogs

Background

Portable blood glucose meters (PBGMs) allow easy glucose measurements. As animal‐specific PBGMs are not available everywhere, those for humans are widely used.

Objectives

To assess the accuracy and precision of 9 PBGMs in canine whole blood (WB) and plasma, based on the ISO 15197:2013.

Animals

Fifty‐nine client‐owned dogs attending the Veterinary Teaching Hospital.

Methods

Analytical evaluation of 100 blood samples was performed for accuracy and 23 for precision (glucose 29–579 mg/dL) following ISO recommendations. A PBGM was considered accurate if 95% of the measurements were within ±15 mg/dL from the reference when glucose was <100 mg/dL and within ±15% when it was ≥100 mg/dL, and if 99% of them were within zones A and B in error grid analysis (EG). A hexokinase‐based analyzer was used as reference. Ninety samples were assessed for hematocrit interferences.

Results

Accuracy requirements were not fulfilled by any PBGM in WB (74% of measurements within the limits for the most accurate) and by 1 only in plasma. However, the EG analysis in WB was passed by 6 PBGM and by all in plasma. The most accurate were also the most precise, with coefficients of variation <5% in WB and <3% in plasma. Hematocrit correlated with bias against the reference method in 4 PBGM (r = −0.243 − [−0.371]; P < .021).

Conclusions and Clinical Importance

This disparity among PBGM suggests that meters approved for humans need to be evaluated before use in other species.

The clinical utility of two human portable blood glucose meters in canine and feline practice

BACKGROUND

Portable blood glucose meters (PBGMs) are useful for serial measurements of blood glucose and creation of blood glucose curves in veterinary practice. However, it is necessary to validate PBGMs designed for people for veterinary use.

OBJECTIVES

Our objective was to evaluate the accuracy of 2 PBGMs designed for people for use in dogs and cats.

METHODS

The blood glucose levels were determined in blood samples collected from 69 dogs and 26 cats admitted to the Kagoshima University Veterinary Teaching Hospital, using a MEDISAFE [PBGM-T] and an Antsense III [PBGM-H], and a FUJI DRI-CHEM 7000V as reference method. The correlations and agreements among the results were statistically analyzed.

RESULTS

Simple regression analyses revealed a high correlation between values from both PBGMs and the reference method in both dogs and cats. However, Passing-Bablok regression and Bland-Altman analyses revealed that the data from both PBGMs did not show statistical agreement with the reference values. Concordance correlated coefficients were moderate for the PBGM-T and almost perfect for the PBGM-H for canine samples, and were poor for the PBGM-T and substantial for the PBGM-H for feline samples. Hematocrit values significantly affected the results of the PBGM-T, but not the PBGM-H. Error grid analyses revealed that all measurements from both PBGMs would lead to acceptable treatment decisions.

CONCLUSIONS

Our findings suggest that both PBGMs, especially the PBGM-H, would be clinically useful in small animal practice, although there was a bias between each PBGM and the reference method.

Evaluation of portable blood glucose meters for measurement of blood glucose concentration in ferrets (Mustela putorius furo)

OBJECTIVE

To evaluate agreement of 3 models of portable blood glucose meters (PBGMs; 2 designed for use with human samples and 1 designed for veterinary use) with a laboratory analyzer for measurement of blood glucose concentrations in ferrets (Mustela putorius furo).

DESIGN

Evaluation study.

ANIMALS

52 ferrets.

PROCEDURES

Samples were analyzed with 4 PBGMs (whole blood) and a laboratory analyzer (plasma). Two PBGMs of the model designed for veterinary use were tested; each was set to a code corresponding to canine or feline sample analysis throughout the study. Agreement and bias between measurements obtained with the PBGMs and the laboratory analyzer were assessed with Bland-Altman plots. Linear regression analysis was performed to evaluate associations with venipuncture site by comparison of central (jugular) and peripheral (lateral saphenous or cephalic) venous blood samples.

RESULTS

Plasma glucose concentrations measured with the laboratory analyzer ranged from 41 to 160 mg/dL. Results from the PBGM for veterinary use coded to test a canine blood sample had the greatest agreement with the laboratory analyzer (mean bias, 1.9 mg/dL); all other PBGMs significantly underestimated blood glucose concentrations. A PBGM designed for use with human samples had the least agreement with the laboratory analyzer (mean bias, -34.0 mg/dL). Blood glucose concentration was not significantly different between central and peripheral venous blood samples for any analyzer used.

CONCLUSIONS AND CLINICAL RELEVANCE

Significant underestimation of blood glucose concentrations as detected for 3 of the 4 PBGMs used in the study could have a substantial impact on clinical decision making. Verification of blood glucose concentrations in ferrets with a laboratory analyzer is highly recommended.

Comparison of point-of-care testing glucose results from intensive care patients measured with network-ready devices

BACKGROUND

Fast and reliable glycemic control is of tremendous importance in intensive care units. Point-of-care devices used in professional care have to be precise and of low variability, and their connectivity has to outrange the abilities of home-care equivalents. In particular, the meter's efficiency should be tested not only with spiked blood samples from healthy donors but also with blood from intensive care unit patients because of their special matrix conditions as low hematocrit, oxygen pressure variability, or medication.

METHODS

Four types of network-ready glucose meters were tested. Data, obtained from native or maltose/xylose-spiked intensive care patients' blood, were compared (oxygen, hematocrit, glucose, and maltose and xylose dependencies) with those from a YSI 2300 STAT Plus™ glucose and lactate analyzer (YSI Life Sciences, Yellow Springs, OH). According to ISO 15197 (2003) acceptance of glucose meter results was determined. Quality control results were investigated considering a new calculation type in German guidelines.

RESULTS

Three of the meters fulfill the overall acceptance criterions. Two of the meters achieved accuracies above 93% in all oxygen, hematocrit, and glucose subgroups. Maltose generates deviations leading to accuracies from 71.1% to 100%, and xylose causes accuracies of 33.3% to 100%.

CONCLUSIONS

State of the art for manufacturing small network point-of-care testing glucose meters has reached a new level of precision, but the devices still have to be handled with care, and in particular the staff of an intensive care unit still needs knowledge about possible interferences.

Selected blood chemistry and gas reference ranges for broiler breeders using the i-STAT handheld clinical analyzer

Selected blood chemistry and gas reference ranges for clinically healthy broiler breeder hens were established using CG8+ cartridges in an i-STAT handheld point-of-care clinical analyzer. Samples from 165 hens (25-36 wk of age), representing three broiler breeder strains reared by four integrators, were evaluated. A standardized sampling technique was developed to minimize instrument error readings. The following reference ranges and means, respectively, were determined: sodium (141.6-152.6, 147.1 [mmol/L]), potassium (4.1-5.7, 4.9 [mmol/L]), ionized calcium (1.20-1.73, 1.47 [mmol/L]), glucose (207.2-260.7, 234.0 [mg/dl]), hematocrit (21.3-30.8, 26.1 [% packed cell volume]), hemoglobin (7.3-10.5, 8.9 [g/dl]), pH (7.28-7.57, 7.42), carbon dioxide partial pressure (25.9-49.5, 37.7 [mm Hg]), oxygen partial pressure (32.0-60.5, 46.2 [mm Hg]), bicarbonate (18.9-30.3, 24.6 [mmol/L]), total carbon dioxide (19.9-31.5, 25.7 [mmol/L]), base excess (-6.8 to 7.2, 0.2), and oxygen saturation (70.6-93.3, 82.0 [%]). Wide ranges in blood gases and base excess occurred in all strains. Cobb strain hens had significantly lower glucose and higher partial and saturated oxygen values compared with two Ross strains. Significant differences in several blood parameters were found among different integrators and in older postpeak production birds. The i-STAT handheld point-of-care clinical analyzer provides rapid, relatively low cost, blood chemistry values that are useful for investigating broiler breeder flock diseases of unknown or uncertain etiology, especially those suspected of having a metabolic cause.

Evaluation of six portable blood glucose meters for measuring blood glucose concentration in dogs

OBJECTIVE

To evaluate accuracy of 6 portable blood glucose meters (PBGMs) by comparing results of these meters with results obtained with a reference chemistry analyzer.

DESIGN

Evaluation study.

ANIMALS

49 dogs (158 blood samples). Procedures-Venous blood samples were tested with the 6 PBGMs, and results were compared with results of a commercially available analyzer that used a reference method based on the hexokinase reaction.

RESULTS

Plasma glucose concentrations obtained with the reference analyzer ranged from 41 to 639 mg/dL. There were significant correlations between blood glucose concentrations obtained with the 6 PBGMs and plasma glucose concentrations obtained with the reference analyzer (r > or = 0.96). However, for all 6 PBGMs, results differed from results for the reference analyzer, with the difference increasing as plasma glucose concentration increased. Significant differences in bias were found among meters. For 142 samples classified as hypoglycemic, euglycemic, or hyperglycemic on the basis of results of the reference analyzer, the percentage of samples that were misclassified on the basis of results of the PBGMs ranged from 2.1% to 38.7%.

CONCLUSIONS AND CLINICAL RELEVANCE

Results of the present study suggested that there were substantial differences in the accuracy of currently available PBGMs when used to determine blood glucose concentration in dogs.

A Pilot Study Comparing the Diabetogenic Effects of Dexamethasone and Prednisolone in Cats

Fourteen cats received either daily prednisolone (4.4 mg/kg per os [PO]) or dexamethasone (0.55 mg/kg PO) for 56 days. These doses were clinically equipotent. Serum fructosamine and urine glucose were measured on days 0, 28, and 56. Insulin sensitivity, glucose tolerance, and peak insulin secretion were measured in each group prior to and at the end of the courses of glucocorticoid administration. On day 56, the prevalence of glucosuria was significantly greater (P=0.027), and a trend was seen toward greater fructosamine concentrations (P=0.083) in dexamethasone-treated cats compared to prednisolone-treated cats. The results of this pilot study also showed a trend toward a greater decrease in insulin sensitivity (P=0.061) and a significantly lower compensatory increase in insulin secretion (P=0.081) in the dexamethasone-treated cats than in cats administered prednisolone. These preliminary data suggest that dexamethasone exhibits greater diabetogenic effects in cats than equipotent doses of prednisolone. Further study is justified to support this hypothesis.

Simple, rapid, and highly sensitive detection of diphosgene and triphosgene by spectrophotometric methods

Methods for the detection and estimation of diphosgene and triphosgene are described. These compounds are widely used phosgene precursors which produce an intensely colored purple pentamethine oxonol dye when reacted with 1,3-dimethylbarbituric acid (DBA) and pyridine (or a pyridine derivative). Two quantitative methods are described, based on either UV absorbance or fluorescence of the oxonol dye. Detection limits are approximately 4 micromol/L by UV and <0.4 micromol/L by fluorescence. The third method is a test strip for the simple and rapid detection and semi-quantitative estimation of diphosgene and triphosgene, using a filter paper embedded with dimethylbarbituric acid and poly(4-vinylpyridine). Addition of a test solution to the paper causes a color change from white to light blue at low concentrations and to pink at higher concentrations of triphosgene. The test strip is useful for quick on-site detection of triphosgene and diphosgene in reaction mixtures. The test is easy to perform and provides clear signal readouts indicative of the presence of phosgene precursors. The utility of this method was demonstrated by the qualitative determination of residual triphosgene during the production of poly(bisphenol-A carbonate).

Avaliação de dois sensores portáteis para mensuração da glicemia em cães

Avaliou-se a precisão analítica e clínica de dois sensores portáteis para mensuração da glicemia em cães. Os valores da mensuração da glicemia obtidos com os sensores foram comparados com aqueles obtidos pelo método padrão da glicose oxidase, por meio da análise de correlação e da análise da grade de erros. Os resultados gerados pelos sensores não foram diferentes do método padrão. Conclui-se que ambos os sensores são adequados para mensuração da glicemia em cães.

Evaluation of the Accutrend for lactate measurement in dogs

BACKGROUND

Lactate concentrations are increasingly quantified in dogs using point-of-care instruments, but often without canine-specific method evaluation and instrument-specific reference intervals.

OBJECTIVES

The objectives of this study were to 1) determine the precision of the Accutrend (Roche Diagnostics) for lactate determination in dogs, 2) determine the accuracy of the Accutrend using the Rapidlab 865 (Bayer Diagnostics) as the reference method, and 3) establish and compare reference intervals for lactate concentration in clinically healthy dogs for both instruments.

METHODS

Precision was evaluated using low and high control materials, and variable (1 drop) and fixed (25 microL) sample volumes. Accuracy was determined by comparing lactate concentrations obtained with the Accutrend with those from the Rapidlab 865 in 273 heparinized canine jugular venous blood samples from 100 clinically healthy dogs and 107 systemically ill dogs (173 samples). Lactate reference intervals were established for both analyzers using data from the 100 clinically healthy dogs.

RESULTS

The precision of the Accutrend was good (coefficients of variation, < or = 5.3%) for 25-microL samples but not when a drop was used. Lactate concentrations obtained on the Accutrend correlated poorly with those from the Rapidlab 865 (r = 0.864, mean bias = 0.66 mmol/L, 95% confidence interval [CI] = 0.57-0.76 with 95% limits of agreement = -0.87 (lower limit, 95% CI = -1.03 to -0.71) and 2.20 (upper limit, 95% CI = 2.04 to 2.36). The reference interval for canine lactate concentration on the Accutrend was 1.2-3.1 mmol/L compared with 0.46-2.31 mmol/L on the Rapidlab.

CONCLUSION

Although precision was good with fixed sample volumes, blood lactate concentrations obtained on the Accutrend were significantly different than those on the Rapidlab 865, with systematic and random errors resulting in a positive bias. Further evaluation of the Accutrend is required before its use in dogs can be recommended.

Use of the i-STAT portable clinical analyzer in mice

The use of portable chemistry analyzers is an attractive option for obtaining clinical pathology panels in mice, because these analyzers require only small volumes of whole blood. However, in studies with other animals, portable analyzers do not always agree with results obtained using standard laboratory equipment. The authors evaluated the use of the i-STAT handheld portable clinical analyzer compared to the use of standard nonportable laboratory instruments in mice. As shown with other species, the i-STAT results did not always agree with standard laboratory instruments; however, the i-STAT does show reliability for certain chemistry assays.

Evaluation of a continuous glucose monitoring system for use in veterinary medicine

BACKGROUND

With the emergence of continuous glucose monitoring systems being used to provide a detailed glucose picture in humans, a commercially available system (CGMS(R), Medtronic Minimed, Northridge, CA) was examined for use in veterinary species.

METHODS

Adult, clinically normal horses (n = 7), cats (n = 3), dogs (n = 4), and cows (n = 5) were studied. Cats (n = 4), dogs (n = 5), and one horse with diabetes were included in the study. Several of the normal horses, including the horse with diabetes, and one cow were subjected to an intravenous glucose tolerance test. The CGMS was attached to each animal, and the recorded interstitial glucose concentrations were compared with whole blood glucose concentrations as determined by a point-of-care glucose meter. Events such as insulin administration, feeding, travel, or administration of intravenous glucose were all noted and compared with results from the CGMS.

RESULTS

There was a positive correlation between interstitial and whole blood glucose concentrations for all the clinically normal species, those with diabetes mellitus, and those receiving intravenous glucose. Events such as feeding, glucose or insulin administration, and transport to the clinic were noted by the owner or clinician and could be identified on the graph and correlated with time of occurrence.

CONCLUSIONS

Our data indicate that the use of the CGMS is valid for use in the species examined. Use of this system alleviated the need for multiple blood samples and the stress associated with obtaining those samples. This system may provide greater monitoring capabilities in patients with diabetes and promote the diagnostic and research potential of serial glucose monitoring in veterinary species.

Evaluation of long-term home monitoring of blood glucose concentrations in cats with diabetes mellitus: 26 cases (1999–2002)

OBJECTIVE

To evaluate owner compliance with longterm home monitoring of blood glucose concentrations in diabetic cats and assess the influence of home monitoring on the frequency of reevaluation of those cats at a veterinary hospital.

DESIGN

Retrospective study.

ANIMALS

26 cats with diabetes mellitus.

PROCEDURE

Medical records of diabetic cats for which home monitoring was undertaken were reviewed, and owners were contacted by telephone. Signalment, laboratory test results, insulin treatment regimen, details of home monitoring, clinical signs during treatment, frequency of follow-up examinations, and survival times were evaluated.

RESULTS

Monitoring of cats commenced within 12 weeks (median, 3 weeks) after initial evaluation; 8 owners were unable to perform home monitoring, and 1 cat was euthanatized after 1 week. In 17 cats, duration of home monitoring was 4.8 to 46.0 months (median, 22.0 months); 6 cats died after 7.0 to 18.0 months (median, 13.0 months). In 11 cats, home monitoring was ongoing at completion of the study (12.0 to 46.0 months' duration). Fourteen owners completed blood glucose curves every 2 to 4 weeks. Cats managed with home monitoring received higher dosages of insulin, compared with cats that were not monitored. Four of 17 cats managed by home monitoring had transient resolution of diabetes mellitus for as long as 1 year. Home monitoring did not affect the frequency of reevaluation at the veterinary hospital.

CONCLUSIONS AND CLINICAL RELEVANCE

Owner compliance with long-term home monitoring appeared to be satisfactory, and home monitoring did not affect the frequency of reevaluation of patients by veterinarians.

Evaluation of a continuous glucose monitoring system for use in dogs, cats, and horses

OBJECTIVE

To evaluate a continuous glucose monitoring system (CGMS) for use in dogs, cats, and horses.

DESIGN

Prospective clinical study. Animals-7 horses, 3 cats, and 4 dogs that were clinically normal and 1 horse, 2 cats, and 3 dogs with diabetes mellitus.

PROCEDURE

Interstitial glucose concentrations were monitored and recorded every 5 minutes by use of a CGMS. Interstitial glucose concentrations were compared with whole blood glucose concentrations as determined by a point-of-care glucose meter. Interstitial glucose concentrations were also monitored in 2 clinically normal horses after oral and i.v. administration of glucose.

RESULTS

There was a positive correlation between interstitial and whole blood glucose concentrations for clinically normal dogs, cats, and horses and those with diabetes mellitus. Events such as feeding, glucose or insulin administration, restraint, and transport to the clinic were recorded by the owner or clinician and could be identified on the graph and associated with time of occurrence.

CONCLUSIONS AND CLINICAL RELEVANCE

Our data indicate that use of CGMS is valid for dogs, cats, and horses. This system alleviated the need for multiple blood samples and the stress associated with obtaining those samples. Because hospitalization was not required, information obtained from the CGMS provided a more accurate assessment of the animal's glucose concentrations for an extended period, compared with measurement of blood glucose concentrations. Use of the CGMS will promote the diagnostic and research potential of serial glucose monitoring.

Home monitoring of blood glucose concentration by owners of diabetic dogs

The objective of this study was to investigate whether home monitoring of blood glucose of diabetic dogs by owners would be possible on a long-term basis. The owners of 12 diabetic dogs were each asked to generate four glucose curves by taking capillary blood samples from their dog's ear, at three- to four-week intervals. Within one week of each curve being produced by the owner, an additional curve was produced by a veterinarian in the hospital. Ten owners were able to generate blood glucose curves; three of them needed a second demonstration, and two telephoned for further guidance. The blood glucose concentrations obtained from the first two 'hospital' curves were significantly lower than those measured at home. Overall, in 42 per cent of cases, the treatment based on the hospital curves would have been different from that based on 'home' curves. The results of this study indicate that the majority of owners were able and willing to perform long-term monitoring of the blood glucose concentrations of their dogs.

Blood values of juvenile northern elephant seals (Mirounga angustirostris) obtained using a portable clinical analyzer

BACKGROUND

Sick, injured, or orphaned juvenile northern elephant seals (Mirounga angustisrostris) treated at rehabilitation centers frequently present with abnormalities in blood sodium, potassium, chloride, BUN, and glucose concentrations, and HCT. These abnormalities could be detected rapidly using a portable blood analyzer, but results with this analysis method do not necessarily equate with those obtained using other techniques.

OBJECTIVE

The objective of this study was to better assess the clinical relevance of values obtained from a portable analyzer and to compare the results with values obtained using more common methods of analysis.

METHODS

Heparinized whole blood samples were collected from 20 rehabilitated juvenile northern elephant seals. A portable clinical analyzer (i-STAT, i-STAT Corp, East Windsor, NJ, USA) was used to establish baseline values. Serum biochemical values were obtained using an automated chemical analyzer (Olympus AU5200, Olympus America, Melville, NY, USA). HCT was determined using EDTA whole blood and a cell counter.

RESULTS

Using the portable analyzer, mean (minimum-maximum) values were obtained for sodium, 143 (132-146) mmol/L; potassium, 4.4 (3.9-5.8) mmol/L; chloride, 106 (101-109) mmol/L; BUN, 1.8 (1.1-2.4) mmol/L; glucose, 7.55 (5.99-8.49) mmol/L; and HCT, 0.55 (0.52-0.61) L/L. Average differences between methods were small for potassium (-0.45 mmol/L), BUN (0.1 mmol/L), and HCT (0.037 L/L) but were large for sodium (-6.8 mmol/L), chloride (-6.4 mmol/L), and glucose (-0.56 mmol/L).

CONCLUSIONS

These results suggest that the i-STAT portable analyzer could be useful for clinically assessing juvenile elephant seals. However, when making medical decisions, the clinician should be aware of differences associated with various analyzers and sample types.

Home monitoring of the diabetic pet

Home monitoring of the diabetic pet is a challenging proposition for many pet owners. Diabetes, unlike many other diseases, requires that the client, not the veterinarian, treat the disease. It is crucial that veterinarians reinforce and educate clients that successful treatment of diabetes mellitus will depend solely on the client's actions throughout the course of the treatment. This article provides guidelines on educating clients in the home monitoring process. This commonsense approach covers elements of in-home monitoring, including general appearance, clinical signs, behavior changes, feeding schedules, and medication administration. Additionally, thorough explanation is provided for clients who wish to take a more active role in obtaining and monitoring blood and urine chemistry values. This information is provided to assist the veterinary technician and veterinarian in educating clients of their responsibility in treating this disease.

Measurement of capillary blood glucose concentrations by pet owners: a new tool in the management of diabetes mellitus

Recently a new method for capillary blood sampling from the ears of dogs and cats was described, which allows the measurement of glucose concentration by means of portable glucose meters. The authors of this report evaluated the suitability of this method for use by pet owners and the potential technical problems. The owners of seven healthy dogs and seven healthy cats were asked to perform two glucose curves (measuring blood glucose concentration every 2 hours for a total of 12 hours). All dog owners and three cat owners were able to perform a reliable blood glucose curve. The most frequently encountered problems were inadequate formation of a blood drop due to excessive digital pressure on the pinna, repeatedly depressing the plunger of the lancet device instead of allowing the negative pressure to slowly build up, and failure to fill the test strip up to the mark. The authors conclude that these steps of the procedure need to be stressed during technique demonstration and that home monitoring of blood glucose concentrations may serve as a new tool in the management of diabetic dogs and cats.

Portable blood glucose meters as a means of monitoring blood glucose concentrations in dogs and cats with diabetes mellitus

The use of portable blood glucose meters (PBGM) has become common in veterinary medicine as a rapid means of monitoring animals' blood glucose in a variety of medical conditions. These hand-held monitors allow for diagnostic and therapeutic decisions to be made quickly and relatively inexpensively using only a small amount of blood. Both in conditions resulting in hyperglycemia, such as diabetes mellitus, and in those resulting in hypoglycemia, such as sepsis or the presence of an insulinoma, veterinarians have come to rely on PBGM to provide critical information on the status of their animal patients. In particular, PBGM are frequently used to measure individual blood glucose values in an animal over a period to create a blood glucose curve when evaluating the effectiveness of insulin therapy in diabetic dogs and cats.

Critical care monitoring considerations for the diabetic patient

Diabetes mellitus (DM) is a common endocrine disease encountered in the emergency and critical care setting. The diabetic Ketoacidotic (DKA) animal represents an extreme of the DM patient with regard to hyperglycemia and acid-base and electrolyte derangements. Prompt diagnosis of DKA in a critical patient and rapid initiation of appropriate therapy are necessary for a positive outcome. The steps of treatment, in order of importance, include initiation of intravenous fluid therapy, insulin therapy, electrolyte replacement, and reversal of the metabolic acidosis. The main goals of therapy--including correction of dehydration, electrolyte abnormalities and acidosis via aggressive fluid therapy with electrolyte supplementation and correction of ketoacidosis and hyperglycemia via initiation of insulin therapy--can be achieved if these steps are followed. Because of the severity of metabolic alterations in the DKA animal, frequent and careful monitoring are paramount because they will allow the clinician to tailor treatment to each case.

Management of canine diabetes

The majority of diabetic dogs appear to have a form of type 1 diabetes analogous to the latent autoimmune diabetes of adults (LADA) in humans. Evidence of acute or chronic pancreatitis occurs in about 40% of diabetic dogs. Blindness caused by cataract formation eventually occurs in the majority of diabetic dogs and is not dependent on glycemic control. Insulin is the mainstay of therapy for diabetic dogs, and a conservative approach to insulin therapy is crucial. Most diabetic dogs require twice-daily dosing with lente or NPH insulin to adequately control their clinical signs. The diet fed should primarily be palatable and nutritionally balanced. Improved glycemic control may be achieved in some dogs if the diet contains increased insoluble fiber.