Analytical validation of an ELISA for measurement of canine pancreas‐specific lipase

Background: The diagnosis of canine pancreatitis is challenging. Clinical presentation often includes nonspecific clinical signs, such as vomiting, anorexia, and abdominal discomfort. Increased serum lipase activity can be indicative of pancreatitis; however, it can also be increased with other conditions. An immunoassay for measurement of canine pancreas‐specific lipase in canine serum that would be suitable for commercial application and provide rapid results would be beneficial. Objective: The goal of this study was to validate the Spec cPL assay, a commercially available ELISA for the quantitative measurement of canine pancreas‐specific lipase. Methods: Dynamic range, dilutional linearity, precision, interfering substances, assay stability, and reproducibility were investigated for analytical validation. The method was compared with the reference assay, canine pancreatic lipase immunoreactivity (cPLI), and included evaluation of a sample population of dogs and bias. Results: Analytical validation showed a dynamic range of 36–954 μg/L; good precision (intra‐ and interassay coefficient of variation <12%); absence of interference from lipid, hemoglobin, or bilirubin; 12‐month kit stability; and good reproducibility. Method comparison showed a positive bias relative to the cPLI reference method; however, the bias can be accommodated by adjustment of decision limits. The upper limit of the reference interval for Spec cPL was determined to be 216 μg/L based on the upper 97.5th percentile of results from 93 clinically healthy, kennel‐housed dogs. Conclusions: Validation data demonstrated that the Spec cPL assay provides reproducible results for canine pancreas‐specific lipase. A readily available assay for measurement of this enzyme allows broader clinical utilization of this analytical tool, generating timely results to aid in the diagnosis of canine pancreatitis.     

Correlating two-dimensional shear wave elastography of acute pancreatitis with Spec cPL in dogs

BackgroundPancreatitis is a common disease in which 37% of dogs had evidence of acute or chronic pancreatitis at necropsy. Although biopsy is still the gold standard to diagnose acute pancreatitis, clinical data including ultrasonographic findings and measurement of canine serum pancreatic lipase immunoreactivity (cPLI) are used in routine. However, it may be insufficient in the diagnostic approach to acute pancreatitis.ObjectivesTo evaluate the clinical diagnostic feasibility of two-dimensional shear wave elastography (2D SWE) on canine acute pancreatitis for enhanced diagnostic confidence.Methods2D SWE was used to assess pancreatic stiffness and determine the correlation between pancreatic shear wave velocity (SWV) and Spec cPL concentration in 31 dogs with healthy pancreas and 10 dogs with acute pancreatitis.ResultsThe pancreatic SWV was significantly higher in the acute pancreatitis group (2.67 ± 0.20 m/s) than in the healthy pancreas group (2.30 ± 0.26 m/s; p < 0.05). The moderate positive correlation was found between the pancreatic SWV and Spec cPL concentration (95% confidence interval, 0.214–0.693; r = 0.489; p < 0.05).ConclusionsThese results indicated that 2D SWE was feasible for assessing pancreatic stiffness in acute pancreatitis, and that pancreatic SWV using 2D SWE correlated with Spec cPL concentration. SWE could provide a quantitative measure of pancreatic stiffness, which can increase the accuracy of diagnosing acute pancreatitis in dogs. The 2D SWE can be used as a complementary imaging modality for diagnosing acute pancreatitis in dogs.     

Serum lipase determination in the dog: a comparison of a titrimetric method with an automated kinetic method

An enzymatic, kinetic method for determining serum lipase activity was evaluated and compared to a standard manual method for use in dogs. The kinetic method was a commercial kit adapted for use on a tandem access clinical chemistry analyzer and utilized a series of coupled enzymatic reactions based on the hydrolysis of 1,2-diglyceride by lipase. The manual method was the Cherry-Crandall technique based on the titration of base against the acid formed by hydrolysis of an olive oil substrate by lipase. The correlation between the two methods was very good (r = 0.94). The reference range for 56 clinically healthy dogs assayed by the kinetic method was 90 to 527 U/L. Diseases associated with a greater than twofold elevation in serum lipase activity as determined by the kinetic method included pancreatitis, gastritis with liver disease, and oliguric renal failure with metabolic acidosis. In some cases, pancreatitis was seen with other clinical problems, such as gastroenteritis, diabetic ketoacidosis, duodenal mass, disseminated intravascular coagulation, and septic peritonitis. Diseases associated with serum lipase activity within the reference range or elevated less than twofold included gastritis, gastric ulcer, cholestasis, phenobarbital-induced hepatopathy, colitis, copper hepatopathy, abdominal hematoma, apocrine gland adenocarcinoma, and thrombocytopenia with pneumonia.     

Increased canine pancreatic lipase immunoreactivity (cPLI) and 1,2-o-dilauryl-rac-glycero-3-glutaric acid-(6′-methylresorufin) ester (DGGR) lipase in dogs with evidence of portal hypertension and normal pancreatic histology: a pilot study

The clinical presentations of both liver disease and pancreatitis are nonspecific and overlapping, which may cause difficulty in diagnosis. In our retrospective pilot study, we assessed whether dogs with evidence of portal hypertension and absence of pancreatitis on pancreatic histology have increases in canine pancreatic lipase immunoreactivity (cPLI) and 1,2-o-dilauryl-rac-glycero-3-glutaric acid-(6′-methylresorufin) ester (DGGR) lipase. We included dogs that had been presented between 2008 and 2019 if they had normal pancreatic histology, histologically confirmed hepatopathy, and if canine pancreas-specific lipase (Spec cPL; Idexx) or DGGR lipase had been measured. Only dogs with portal hypertension were included. Six dogs fulfilled the inclusion criteria. Four of 6 and 2 of 6 dogs had Spec cPL and DGGR lipase exceeding the upper reference limit, respectively. From the 4 dogs with increased Spec cPL, 2 had concentrations of 200–400 µg/L and 2 had concentrations ≥ 400 µg/L. Our results suggest that canine portal hypertension might lead to increased Spec cPL and DGGR lipase values in the absence of pancreatitis on histology. Until more evidence in a larger number of dogs with portal hypertension is available, both tests should be interpreted cautiously in the presence of portal hypertension.