Serum lipase activity in dogs can be measured by different types of assays. Most assays utilize a 1,2-diglyceride as a substrate, others triolein, and yet others DGGR. This latter substrate has been utilized in human medicine for more than 20 years. However, recently some reports have suggested that DGGR-based assays are specific for the measurement of pancreatic lipase in dog serum. Dogs with exocrine pancreatic insufficiency (EPI) are considered to have lost more than 90% of their secretory capacity. Thus, the aim of this study was to measure serum lipase activity by a DGGR-based assay in dogs with EPI and compare them to serum lipase activities in healthy dogs.
Leftover serum samples from 48 dogs with a serum cTLI concentration ≤ 1.0 µg/L were selected. Serum samples from 66 healthy dogs were used as controls. Serum lipase activity was measured by a DGGR-based assay and was compared between dogs with EPI and healthy control dogs. The number of dogs with EPI with a serum lipase activity within the reference interval was determined.
Serum lipase activity was significantly lower in dogs with EPI (median: 34 U/L; range: 20–94 U/L) than that in healthy control dogs (median: 74 U/L; range: 23–308 U/L; p-value: < 0.0001). However, 33/48 EPI dogs (69%) had serum lipase activities within the reference interval (31–174 U/L), suggesting that DGGR is not exclusively hydrolyzed by pancreatic lipase and DGGR-based assays are thus not specific for this enzyme. Which other lipases are detected by DGGR-based assays remains to be determined.