Rapid measurement of serum pancreatic amylase

A simple, rapid assay for the pancreatic isoenzyme of human serum amylase was developed. The assay utilized an immunoabsorbent prepared by coating latex beads with a monoclonal antibody specific for pancreatic amylase. Treatment of patient serum with immunoabsorbent removed pancreatic amylase, and measurement of residual amylase activity with standard total amylase methodology allowed estimation of the pancreatic amylase content. Extraction efficiency of pancreatic amylase was consistent at amylase concentrations up to 1,000 U/L (y = 0.97 x +16.7 U/L; r = 0.9995). The assay was standardized with purified pancreatic amylase added to neonatal serum (low endogenous activity). A comparison of patient specimen results with the results of a standard technique (cellulose acetate electrophoresis) yielded an excellent correlation (immunoabsorption result = 0.96 electrophoresis result + 1.2 U/L; r = 0.987). Salivary amylase did not interfere with the assay until levels exceeded 1,000 U/L. Daily analysis of a frozen serum pool yielded a coefficient of variation of 9.2% at mean pancreatic amylase value of 54 U/L (+/- 5 U/L). A normal range study found a strong influence of age, with pancreatic amylase levels increasing dramatically in the first 3 years of life, to stabilize at a range of 0-66 U/L thereafter.