Lipases hydrolyze triglycerides. There are several forms of lipase: pancreatic lipase, colipase and lipoprotein lipase. Lipoprotein lipase is produced by vascular endothelium and is essential in triglyceride metabolism.


Assay methods

These are based on hydrolysis of an olive oil emulsion into constituent fatty acids.

  • Titrometric: This estimates the quantity of sodium hydroxide needed to neutralise fatty acids produced by lipase activity.
  • Nephelometry: Triolein (long chain fatty acids) is degraded to diglycerides. The degradation of triolein results in decreased turbidity. Hemolysis and icterus can result in falsely low activity.
  • Colorimetric: Measures the rate of dye formation yielded from the breakdown of long chain fatty acids (such as 1,2-o-dilauryl-rac-glycero-3-glutaric acid or 1,2-diglyceride), and is the current procedure used at Cornell. 


Procedure at Cornell University

  • Method: The assay uses a 1,2-o-dilauryl-rac-glycero-3-glutaric acid- (6’-methylresorufin) ester (DGGR) as a substrate for lipase activity. The DGGR ester is cleaved by the catalytic action of lipase, in an alkaline solution, to form 1,2‑O‑dilauryl‑rac‑glycerol and an unstable intermediate, glutaric acid‑(6‑methylresorufin) ester. This decomposes spontaneously in alkaline solution to form glutaric acid and methylresorufin. The rate of formation of methylresorufin, which is a red dye, is measured. Addition of a detergent and colipase is supposed to increase the specificity of the assay for pancreatic lipase.
  • Reaction type: Kinetic enzymatic colorimetric.
  • Limits of quantification: 3-300 U/L per manufacturer. Higher results are reported out after dilution to get results within this range.
  • Lower limit of detection: 2 U/L (mean ± 3 SD of a blank, per package insert). In-house studies of a blank solution yielded zero activity. Serial dilution of a sample of 256 U/L showed linearity to 2 U/L.
  • Precision: In-house studies shows an intra-assay coefficient of variation of 0.6-1.3% in samples from a kit from the manufacturer that is designed to measure precision. 

Sample considerations

Sample type

Serum or heparinized plasma, body cavity fluid samples. 


Stability in human samples is 1 week at room temperature or 4ºC and 1 year at -20C (per package insert). Lipase activity in canine serum with the DGGR assay did decrease with frozen storage after 20 days (Graca et al 2005).


  • Lipemia, hemolysis, and icterus: No interference is seen in human samples with a hemolytic index up to 1000 units, turbidity index of up to 2000 units (the turbidity index correlates weakly to triglyceride concentrations and lipemia) or an icteric index up to 60 units. Spiking of canine samples with hemoglobin to a hemolytic index of 1000 units or 20% intralipid® did not affect activities (Graca et al 2005).
  • Drugs: Corticosteroids are reported to increase lipase activity with the 1,2 diglyceride substrate.

Test interpretation

Measurement of lipase is most commonly performed to diagnose pancreatitis. Reported causes of increased lipase activity appear to be substrate dependent. The older 1,2 diglyceride-based assays appear less sensitive than the newer DGGR-based assay (see below). 

Increased activity (hyperlipasemia)

  • Pathophysiologic
    • Acute pancreatitis: Destruction of pancreatic acinar tissue results in the escape of pancreatic enzymes into the pancreas and peritoneal cavity. The enzymes enter the blood by way of lymphatics or capillaries with subsequent increase in serum or plasma activity. 
      • DGGR assay: Graca et al (2005) compared lipase activity results with the DGGR and 1,2 diglyceride assays in 30 dogs with vomiting and diarrhea, 50% of which had pancreatitis. Dogs with pancreatitis had to have 1 or more of anorexia, vomiting, diarrhea, depression and physical examination findings of 1 or more of dehydration, abdominal pain, icterus, or fever and ultrasonographic evidence of pancreatitis (which is not sensitive or specific). They found the DGGR assay had 93% sensitivity and 53% specificity versus the 1,2 diglyceride assay, which had lower sensitivity of 60% and possibly higher specificity of 73% (no confidence intervals provided). Both assays had similar area under the curve of 0.7 (reasonable performance). Another study by Kook et al (2014) compared this assay to a Spec cPL (ELISA-based assay for pancreatic lipase), which is considered the gold standard, in 142 dogs. The results showed good agreement with the Spec cPL (0.795 kappa coefficient at a lipase activity of >108 U/L and >200 ug/L spec cPL or suspicion of pancreatitis). Similarly, a study by Oppliger et al (2013) showed good concordance with the Spec fPL in cats with pancreatitis (both clinically diagnosed and histologically confirmed cases with a kappa coefficient of 0.68, at a lipase activity of >26 U/L and >5.3 ug/L Spec fPL). The results of either assay (Spec fPL or DGGR-based lipase, using the above cut-offs) did not correlate well with ultrasonographic evidence of pancreatitis in a study of 161 cats with suspected pancreatitis (Oppliger et al 2014). Our established intervals on clinically healthy dogs (n=122) have a higher upper limit than that published previously for dogs (Graca et al 2005 [n=56], Kook et al 2015, [n=75]). In contrast, our upper reference limit for cats (n=102) is similar to that published previously (Oppliger et al 2013, n=80).
      • 1,2 diglyceride assay: Increases of at least 2 x normal were seen in dogs and cats with pancreatitis. In dogs, lipase activity increases within 24 hours and peaks (at a higher level than amylase) at 2-5 days. Increases of 3 times normal supported a diagnosis of pancreatitis more strongly than more moderate increases, which may be accounted for by non-pancreatic causes. Lipase activity may be normal in up to 28% of dogs with pancreatitis. In the cat, lipase activity is not consistently increased in pancreatitis. Using this assay, we have diagnosed pancreatitis in horses based on lipase activity in abdominal fluid > activity in serum (Ollivett et al 2012). The diagnostic utility of lipase activity in horses remains to be assessed.
    • Gastrointestinal disease:
      • DGGR assay: There is limited data available. In house studies on low numbers of animals suggests that lipase activity may be increased in dogs with gastrointestinal disease, but it is unclear if these dogs have concurrent mild pancreatitis. not increased with severe azotemia in dogs, but may be
      • 1,2 diglyceride assay: Peritonitis, gastritis, bowel obstruction, and visceral manipulation (laparotomy) may increase lipase activity by 2-3 x normal.
    • Hepatic disease:
      • DGGR assay: No data available.
      • 1,2 diglyceride assay: Hepatic disease and neoplasia may increase activities.
    • Azotemia:
      • DGGR assay: There is limited data available. In house studies on low numbers of animals suggests that lipase activity is not increased with severe azotemia in dogs. 
      • 1,2 diglyceride assay: Increases of up to 4 x normal activity may be seen in patients with decreased GFR. In azotemic patients with lipase activity greater than 3-4 times normal, a diagnosis of pancreatitis should still be considered.