A Rapid Thin Layer Test for Macroamylase With Observations on the Nature of Macroamylase in Six Patients

Abstract

A rapid thin layer Sephadex G-100 filtration method for detection of macroamylase is described. Twelve serum samples of 5 μliters each are assayed in 3 hr on a single thin layer plate. Amylase is detected by reaction with amylopectin coupled with Reactone Red Β (Dy-Amyl). Three (5.9%) of 51 consecutive patients with elevated serum amylase screened by this technique were found to have macroamylasemia. Three additional patients, whose macroamylase was first identified by column chromatography, are also reported. The thin layer technique detected 20 Somogyi units per 100 ml of normal molecular weight amylase, and 35 to 63 Somogyi units per 100 ml of macroamylase. The discrepancy of sensitivity for normal amylase and macroamylase is attributed to dissociation of macroamylase into normal molecular weight amylase during filtration. Dissociation during chromatography at pH 7.2, which is not characteristic of antigen-antibody complexes, was documented. The degree of dissociation varied with different macroamylases, but was consistently reduced by increasing the amount of serum chromatographed.