Comparing two blood tests for pancreatitis in cats

Abstract

BACKGROUND: Serum lipase activities measured by catalytic assays are claimed to be of limited utility for diagnosing pancreatitis in cats. The Spec fPL assay currently is believed the most sensitive test; however, studies comparing different lipase assays are lacking. 1,2-o-dilauryl-rac-glycero-3-glutaric acid-(6'-methylresorufin) ester (DGGR) assay for the determination of lipase activity has been evaluated in dogs, but no information is available in cats. OBJECTIVES: To investigate the agreement of DGGR-lipase activity and Spec fPL concentration in cats with clinical signs consistent with pancreatitis. ANIMALS: Two hundred fifty-one client-owned cats. METHODS: DGGR-lipase activity and Spec fPL concentration measured from the same blood sample in cats undergoing investigation for pancreatitis. The agreement between DGGR-lipase and Spec fPL at different cutoffs was assessed using Cohen's kappa coefficient (κ). Sensitivity and specificity were calculated for 31 cases where pancreatic histopathology was available. RESULTS: DGGR-lipase (cutoff, 26 U/L) and Spec fPL (cutoff, >5.3 μg/L) had a κ of 0.68 (standard error [SE] 0.046). DGGR-lipase (cutoff, 26 U/L) and Spec fPL (cutoff, >3.5 μg/L) had a κ of 0.60 (SE, 0.05). The maximum κ at a Spec fPL cutoff >5.3 μg/L was found when the DGGR-lipase cutoff was set >34 U/L and calculated as 0.755 (SE, 0.042). Sensitivity and specificity were 48% and 63% for DGGR-lipase (cut-off, 26 U/L) and 57% and 63% for Spec fPL (>5.3 μg/L), respectively. CONCLUSIONS AND CLINICAL IMPORTANCE: Both lipase assays agreed substantially. DGGR assay seems a useful and cost-efficient method compared to the Spec fPL test.