Evaluation of Lipase Activity in Serum by Radial Enzyme Diffusion

Results of determination of serum lipase by radial enzyme diffusion correlate well with those by a titrimetric reference method in the abnormal range. The specificity of the dif-fusion assay allows the differentiation of patients with pancreatic disease, even when the lipase activity of the serum is within the normal limits of the titrimetric assay. Pancreatic lipase is not detectable by the diffusion assay in the serum of individuals who are free from pancreatic disease. Additional Keyphrases: pancreatic disease #{149} titrimetry compared #{149}tissue lipases #{149} urinary lipase #{149} enzyme-binding inhibitor Determination of lipase activity in serum is useful in the evaluation of diseases of the pancreas (1). Several procedures in routine use for measurement of lipase activity are based on the Cherry and Crandall method (2, 3) in which olive oil is hydrolyzed and the fatty acids formed are measured titrimetrically. Alternatively, the fatty acids liberated have been determined by the for-mation of their copper soaps (4). Other tests of lipase activity are based on the clearing of very dilute emul-sions of olive oil (5, 6). The assay we describe here depends on measurement of the zones of clearing of a turbid emulsion of olive oil immobilized in buffered agarose by radial enzyme dif-fusion of lipase in the gel. The zone of clearing is shown to be proportional to the enzyme activity in the serum. The method is rapid, requires only a small sample, is easily performed, and is adequately sensitive. The re-sults are compared with those obtained by the titri-metric assay of Tietz and Fiereck (3)