[Determination of the catalytic activity of lipase in serum by measurement or estimation of the pH decrease in a...

In the enzymic hydrolysis of triolein by lipase in serum, hydrogen ions are produced which lead to a decrease in the pH of the test system. The extent of this pH change depends on the catalytic activity of the lipase and on the buffering capacity of the test system. In the method described for the determination of the catalytic activity of lipase in serum, the decrease in pH is measured and recorded potentiometrically. Comparative studies showed a satisfactory correlation of results with those from the continuous titrimetric method. Further studies were performed with a modification of the detection method described by Härtel et al. ((1971) Z. Klin. Chem. Klin. Biochem. 9, 396-397), based on the estimation of the pH decrease from the colour change of an indicator. With operator experience, this test also gives reproducible results for the catalytic activity of lipase in serum.