Evaluation of two reagent strips and three reflectance meters for rapid determination of blood glucose concentrations

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.

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.

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.

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.

Suspected pseudohypoparathyroidism in a domestic ferret

A 1.5-year-old ferret examined because of seizures was found to have low serum calcium, high serum phosphorus, and extremely high serum parathyroid hormone concentrations. Common causes of these abnormalities, including nutritional secondary hyperparathyroidism, chronic renal secondary hyperparathyroidism, tumor lysis syndrome, and hypomagnesemia, were ruled out, and a tentative diagnosis of pseudohypoparathyroidism was made. Pseudohypoparathyroidism is a hereditary condition in people that, to our knowledge, has not been identified in ferrets previously and is caused by a lack of response to high serum parathyroid hormone concentrations, rather than a deficiency of this hormone. The ferret improved after treatment with dihydrotachysterol (a vitamin D analog) and calcium carbonate. It was still doing well after 3.5 years of continued treatment.

Assessment of five portable blood glucose meters for use in cats

OBJECTIVE

To evaluate the clinical and analytic accuracy of 5 portable blood glucose meters (PBGM) in cats, with emphasis on the detection of potential sources of error.

ANIMALS

200 cats.

PROCEDURE

Venous blood glucose readings from 5 PBGM were compared with the results of a hexokinase reference method. Agreement among methods was determined by error grid analysis and statistical methods.

RESULTS

A total of 2,975 PBGM readings and 513 reference values were analyzed. The accuracy of the PBGM varied in different glycemic ranges. The largest differences between PBGM readings and reference values were in the high glycemic range; 4 PBGM underestimated and 1 PBGM overestimated the reference values in most instances. In the low and reference glycemic ranges, the absolute differences between PBGM readings and reference values were small. Despite the analytic differences in accuracy, 4 PBGM had 100% and 1 PBGM had 98.7% of readings in the clinically acceptable values of the error grid analysis. Within- and between-day precisions were good for all PBGM. Significant differences were not detected between readings of EDTA and lithium-heparinized blood and fresh blood without anticoagulant. Compared with these blood types, 1 PBGM had significantly different readings with fluoride anticoagulated blood. In blood samples with a low Hct, all PBGM overestimated glucose concentrations. Sample volumes < 3 microl resulted in inaccurate measurements in 3 PBGM.

CONCLUSIONS AND CLINICAL RELEVANCE

Performance varied among the 5 PBGM analyzed; however, all PBGM were deemed acceptable for clinical use in cats.

Capillary blood sampling from the ear of dogs and cats and use of portable meters to measure glucose concentration

Two new methods for collection of capillary blood from the ear of dogs and cats for the measurement of blood glucose concentration using portable blood glucose meters (PBGMs) are described. The first method uses a lancing device after pre-warming the ear, while the second employs a vacuum lancing device. Both methods generated blood drops of adequate size, although the latter method was faster and easier to perform. Accuracy of the two PBGMs was evaluated clinically and statistically. Although assessment of statistical accuracy revealed differences between the PBGMs and the reference method, all of the PBGM readings were within clinically acceptable ranges. Measurement of capillary blood glucose concentration is easy to perform, inexpensive and fast. It may be used by owners to determine blood glucose concentrations at home, and could serve as a new tool for monitoring diabetic dogs and cats.

Evaluation of five portable blood glucose meters for use in dogs

OBJECTIVE

To evaluate clinical and analytical accuracy of 5 portable blood glucose meters (PBGM) used to measure blood glucose concentrations in dogs and to determine potential sources of error.

DESIGN

Prospective study.

ANIMALS

221 dogs.

PROCEDURE

Venous blood samples were obtained, and results of the 5 PBGM were compared with results of a hexokinase reference method. Agreement among methods was determined by use of error grid analysis and statistical methods.

RESULTS

Accuracy of the PBGM varied with glucose concentration of the sample. The largest differences between results of the PBGM and results of the reference method were obtained with samples with high glucose concentrations; 4 PBGM tended to underestimate and 1 PBGM tended to overestimate the true glucose concentration. Absolute differences between results of the PBGM and results of the reference method were small for samples with low glucose concentrations and samples with concentrations in the reference range. None of the PBGM yielded measurements that would result in clinically unacceptable errors. Within-run and between-day precision was good for all PBGM, and results were not affected by use of EDTA or heparin to anticoagulate blood. Readings of the PBGM were significantly higher for blood samples with low Hct than for samples with normal Hct. For 3 PBGM, samples < 3 microliters resulted in inaccurate measurements.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that currently available PBGM are sufficiently accurate for use in clinical practice to determine blood glucose concentrations in dogs.

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.

Long-term monitoring of the diabetic dog and cat. Clinical signs, serial blood glucose determinations, urine glucose, and glycated blood proteins

Management of diabetic dogs or cats requires the use of all available monitoring technology (Fig. 6). First, one should ask questions about the clinical control of DM. Are the clinical signs of DM resolved, and is the owner satisfied with insulin therapy? Other important questions would include: Is the dog or cat developing long-term complications of diabetes such as neuropathies or cataracts? Is body weight remaining stable? Is the dog or cat showing any signs of hypoglycemia? One should determine if the blood glucose curves are close to ideal for the type of insulin being administered. Urine glucose and ketones should be negative or trace as assessed by the at-home monitoring by the owner. In the problem diabetic, long-term glucose control can be assessed by serum fructosamine or glycosylated hemoglobin determinations. Regulation of the diabetic patient is accomplished when the owner is satisfied with the therapy and when the serum glucose monitoring parameters are acceptable.