The variation in excretory urinary glycyl-prolyl dipeptidyl aminopeptidase in dogs

Effects of time on differential leucocyte counts and biochemical parameters of ovariohysterectomy, gastrotomy and intestinal resection and anastomosis in Nigerian indigenous dogs

Differential leucocytes counts and some biochemical parameters could be affected over time by surgical procedures leading to kidney failure. Hence this study evaluates the effects of ovariohysterectomy (OVH), gastrotomy (GAT) and intestinal resection and anastomosis (ITR) on differential leucocyte counts and some biochemical parameters in Nigerian dogs. Twelve dogs of both sexes weighing 10.8±0.7 kg were randomly divided into three experimental groups of four each. The dogs were pre-treated with atropine sulphate (0.04 mg/kg), Xylazine (2 mg/kg) and propofol (6 mg/kg) parenterally, for induction and maintenance of anaesthesia. Pentazocine (3 mg/kg) was injected after surgery. Pre and post-surgery blood samples were obtained at 0, 2, 24, 48, 72, 96, 120 and 144 h respectively to determine differentials in leucocyte counts, electrolytes, lactate, blood urea nitrogen (BUN) and serum creatinine. Mathematical formulas were used to calculate plasma creatinine, creatinine clearance, plasma creatinine clearance, creatinine half- life, urine creatinine and urine volume. There were significant increases (p ≤ 0.05) in mean sodium, chloride and bicarbonate concentrations at 2, 24, 48, 72, 96 and 120 h post-surgery in group 1 and 2, while group 3 had significant decreases (p ≤ 0.05) in sodium, chloride and bicarbonate ions. Lactate value decreased significantly (p<0.05) in group 1, and increased in group 2 and 3 respectively.BUN increased significantly (p<0.05) in group 1,2 and 3.However, there were significant increases (p<0.05) in lymphocyte concentrations in group 1 and 3, respectively. Monocytes decreased significantly (p<0.05) after surgery. Conclusion: Xylazine and propofol anaesthetics cause hyperlactatemia which can be detrimental in surgical patients with co-morbidities.

Inaccuracy of routine creatinine measurement in canine urine

BACKGROUND

Urine creatinine concentration often is used in ratios such as urine protein:creatinine to compensate for dilution or concentration of spot urine samples.

OBJECTIVE

The purpose of this study was to compare the accuracy of different techniques of urine creatinine measurement currently available for veterinary practitioners.

METHODS

In 104 samples of canine urine diluted 1:20 with distilled water, creatinine concentration was measured using a kinetic Jaffé reaction assay, and an enzymatic technique on an automatic analyzer (Elimat) and 3 benchtop analyzers (Reflovet, Scil; Vitros DT2, Ortho-Clinical Diagnostics; Vettest 8008, IDEXX) used in veterinary practice.

RESULTS

The Jaffé and enzymatic techniques on the Elimat were not significantly different, and their inaccuracy tested with human control urines was <5%. The benchtop analyzers underestimated creatinine concentration, especially at concentrations >2000 mg/L. Inaccuracy was higher with multilayer slide technology systems (Vitros and Vettest) than with the Reflovet system. Results were approximately 25% and 2% lower, respectively, than with the Elimat at urine creatinine concentrations about 2000 mg/L.

CONCLUSION

Inaccuracy in urine creatinine measurements using benchtop analyzers should be taken into account when defining decision thresholds, which should be corrected according to the method used to avoid misinterpretations.

Creatinine in the Dog: A Review

Creatinine is the analyte most frequently measured in human and veterinary clinical chemistry laboratories as an indirect measure of glomerular filtration rate (GFR). Although creatinine metabolism and the difficulties of creatinine measurement have been reviewed in human medicine, similar reviews are lacking in veterinary medicine. The aim of this review is to summarize information and data about creatinine metabolism, measurement, and diagnostic significance in the dog. Plasma creatinine originates from the degradation of creatine and creatine phosphate, which are present mainly in muscle and in food. Creatinine is cleared by glomerular filtration with negligible renal secretion and extrarenal metabolism, and its clearance is a good estimate of GFR. Plasma and urine creatinine measurements are based on the nonspecific Jaffé reaction or specific enzymatic reactions; lack of assay accuracy precludes proper interlaboratory comparison of results. Preanalytical factors such as age and breed can have an impact on plasma creatinine (P-creatinine) concentration, while many intraindividual factors of variation have little effect. Dehydration and drugs mainly affect P-creatinine concentration in dogs by decreasing GFR. P-creatinine is increased in renal failure, whatever its cause, and correlates with a decrease in GFR according to a curvilinear relationship, such that P-creatinine is insensitive for detecting moderate decreases of GFR or for monitoring progression of GFR in dogs with severely reduced kidney function. Low sensitivity can be obviated by determining endogenous or exogenous clearance rates of creatinine. A technique for determining plasma clearance following IV bolus injection of exogenous creatinine and subsequent serial measurement of P-creatinine does not require urine collection and with additional studies may become an established technique for creatinine clearance in dogs.