Progression of lipase activity and pancreatic lipase immunoreactivity in clinically healthy cats and cats with diet-responsive enteropathy

Objectives: The aim of the present study was to describe the course of lipase activity, pancreatic lipase immunoreactivity (PLI) and clinical findings over time in cats. Methods: Four clinically healthy cats and two diarrhoeic cats from a research colony aged 2-8 years with normal haematology and serum biochemistry results were followed up with lipase measurements over a total of 12 months in this descriptive study. Lipase activity (LIPCRoche; reference interval [RI] 8-26 U/l) was determined at day 0, and lipase activity and concurrent PLI (Spec fPL; RI 0-4.4 µg/l) were determined at days 19, 47, 54, 221 and 369. All cats were examined weekly. The pancreas and gastrointestinal tract of all cats were examined via ultrasonography.ResultsLipase activity and PLI in four clinically healthy cats was in the range of 10-283 U/l (median 69) and 1.2-86 µg/l (median 13), respectively. Lipase activity and PLI in two cats with enteropathy was in the range of 16-130 U/l (median 42) and 1.9-36 µg/l (median 8.3). The magnitude and nature of change were always the same for both assays. The correlation between assays was very high ( 0.984; <0.0001). The pancreas was normal on ultrasound in both diarrhoeic cats and two healthy cats, whereas a hypoechoic and enlarged pancreas was found in two clinically healthy cats with persistently increased lipase values. All cats had ultrasonographic evidence of enteropathy. No pattern could be recognised in the temporal lipase progression; only one healthy cat with an ultrasonographically abnormal pancreas had continuously increasing values. Both cats with large bowel diarrhoea were diet-responsive. Conclusions and relevance: Lipase activity and PLI varied from normal to markedly increased in clinically healthy cats and cats with diet-responsive enteropathy and a normal pancreas on ultrasonography. Both lipase assays yielded virtually identical results. No apparent association between lipase results and clinical or ultrasonographic findings was found. The results illustrate the difficulties clinicians face when trying to assess the significance of lipase levels in cats.