Macrolipasemia: a rare cause of persistently elevated serum lipase.

This report describes a variant form of lipase found in a patient with cryptogenic liver cirrhosis. Serum lipase in this patient showed persistently increased activity with simultaneously normal activity of amylase. Results of exclusion chromatography demonstrate that the lipase activity in the serum of this patient eluted as a macromolecule. Since macromolecular complexes were not fixed by protein A, it seems unlikely that lipase is attached to IgG. Tests of the sera from 20 patients with raised serum lipase activity in acute pancreatitis or an acute episode of chronic pancreatitis revealed, in two patients, that a small but reproducible proportion of the total lipase activity eluted in the region of the macrolipase. In addition, 10% and 18% of the total lipase activity was found in the elution region of the macrolipase in two commercial pooled sera used for quality control. The results show that, in rare cases, macrolipasemia must be considered a possible cause of raised serum lipase activity.