Effects of medical history and clinical factors on serum lipase activity and ultrasonographic evidence of pancreatitis: Analysis of 234 dogs

Background Lipase measurements and ultrasonographic (US) evidence of pancreatitis correlate poorly. Objectives Identify explanations for discrepant lipase and pancreatic US results. Animals Two hundred and thirty‐four dogs with gastrointestinal signs. Methods A retrospective study was conducted, in which lipase activity and US were performed within 30 hours. Medical history, clinical examination results, lipase activity, and US results were recorded. Results Lipase and US results were weakly correlated ( r s  = .25, P  < .001). At both evaluated time cut‐offs, median lipase activities were significantly higher with shorter durations of clinical signs before presentation (≤2 days, 334 U/L; >2 days, 118 U/L; P  = .03; ≤7 days, 334 U/L; >7 days, 99 U/L; P  = .004), but US was not significantly more frequently positive. For both cut‐offs (>216/≤216 U/L, >355/≤355 U/L; reference range, 24‐108 U/L), median disease duration was significantly shorter (3 vs 4 days) with higher lipases. Previous pancreatitis episodes were significantly associated with an US diagnosis of pancreatitis ( P  = .04), but median lipase activities were not significantly higher (386 U/L vs 153 U/L; P  = .06) in these dogs. Pancreatic US was significantly more often positive when the request contained “suspicion of pancreatitis” ( P  < .001) or “increased lipase” ( P  = .01). Only changes in pancreatic morphology, echogenicity, and peripancreatic mesentery were significantly associated with a positive US diagnosis, and also had significantly higher lipase activities. Conclusions and Clinical Importance Duration of clinical signs before presentation differently affects laboratory and US evidence of pancreatitis. Previous pancreatitis episodes and information given to radiologists influence US results. These findings can be helpful for future studies on pancreatitis in dogs.