Prevalence of macroamylasaemia using polyethylene glycol precipitation as a screening method.

Four hundred and fifty-four subjects with hyperamylasaemia were screened for the presence of macroamylase using polyethylene glycol precipitation (PEG) and the Beckman automated amylase assay based on the hydrolysis of maltotetraose. Twenty-five subjects (5.5%) exhibited PEG precipitation values suggestive of macroamylasaemia (MA) (>52% loss of original amylase activity). Macroamylasaemia was confirmed by gel filtration chromatography (GFC) in 21/25 subjects, using albumin as a molecular weight marker. Biochemical and clinical details of the 21 subjects identified are presented and discussed. It is recommended that serum exhibiting more than 57% precipitation of the original amylase activity by PEG should be examined by GFC to confirm or exclude MA.