Performance evaluation of “Cygnus-auto LIP” using synthetic substrate DGGMR for lipase measurement

Abstract

Lipase levels in blood are routinely measured for the diagnosis of acute pancreatitis. Such measurements are performed by colorimetric or synthetic substrate assays; however, these assays have not yet been standardized. In this study, we evaluated the performance of a new reagent for lipase measurement, “Cygnus-auto LIP”, using the synthetic substrate “DGGMR”. The coefficients of variation for within-run and between-day reproducibilities were 1.0% to 1.4% and 0.8% to 2.1%, respectively. In the accuracy test conducted using JCCLS CRM 001c, the biases from the reference values were +2.6% for Cygnus-auto LIP and −53.5% for the Nescauto VN lipase. We hypothesize that the large difference was due to the choice of the standard material. The range of the linear quantification of lipase levels is between 4.0 and 460 U/L. This range is sufficient for the diagnosis of acute pancreatitis, since usual lipase levels are approximately twice the maximum reference value. The reagent is stable within 30 days after initial use. To test the interference of various substances, the presence of sodium azide showed at least a 20% decrease in the measured lipase levels. However, this improved reagent did not change the measured lipase levels. A significant correlation was observed between Cygnus-auto LIP and Nescauto VN lipase levels, but the actual measured values were very different. The lipase levels were successfully measured using Cygnus-auto LIP under any conditions. Therefore, this reagent may be a candidate for standardized routine use.