LAUSR

Abstract Background Lipase activity and pancreatic lipase immunoreactivity (PLI) have not been compared in dogs hospitalized for acute pancreatitis (AP). Objectives To describe the progression of lipase activity and PLI, and correlations with clinicopathologic features in dogs with AP. Animals Thirty‐nine dogs with AP based on clinical signs and lipase activity >350 U/L (reference interval [RI], 24‐108 U/L). Methods Retrospective study. Lipase activity (LIPC Roche), PLI (SpecPL), and clinical signs were recorded daily. Admission (d1) data (clinical, laboratory, and ultrasound [US] findings), and clinical signs during hospitalization (d2‐d3) were assessed for correlation with lipases. Results Median (range) duration of clinical signs before presentation was 2 days (1‐7 days). Median (range) lipase activity and PLI at d1 were 1070 U/L (range, 357‐1500 U/L) and 1111 μg/L (range, 292‐1500 μg/L). Strong correlation between assays at d1 (r s 0.96; P < .0001; n = 39), remained equally strong on d2 (r s 0.964; P < .0001; n = 39), and d3 (r s 0.966; P < .0001; n = 22). On d2, lipase activity and PLI were within RI in 13/39 (33%) and 18/39 (46%) of cases. Lipase activities were minimally increased (median, 124 U/L) in 5 dogs with d2 PLI <200 μg/L. On d3, 4 more dogs had normal lipase activity and PLI, and the nature and magnitude of change were always the same for both assays. Clinical signs were not associated with lipases. Only a hyperechoic mesentery, but not an US diagnosis of AP, correlated significantly with lipase activity and PLI. Conclusions and Clinical Importance Lipase decreases rapidly to near or within RI within 2 days of treatment in the majority of dogs with AP. Both lipase assays yielded virtually identical results. Mesenteric echogenicity may be an early marker of AP in dogs.