Fluctuations in serum amylase in patients with macroamylasemia.

Abstract

To report wide fluctuation of serum amylase in patients with macroamylasemia. It has generally been considered to remain constant. Over the past 16 y, 18 patients have been diagnosed with macroamylasemia in our GI department. Of these, four patients were followed up with serial serum amylase determinations for a period of less than 1-4 y. Serum amylase was measured by the "Phadebas amylase test." Serum macroamylase was measured by "PEG precipitation technique." There was a wide fluctuation of serum amylase in three out of four patients. In the fourth patient, more persistent hyperamylasemia was noted during the shorter observation period. Marked fluctuation in serum amylase, ranging from 115 to 1160% in this study, may occur in patients with macroamylasemia. The reasons for these fluctuations are not clear but may be due to association-dissociation of amylase with serum proteins at variable time intervals. This fluctuation, especially when the amylase becomes normal (as in cases 1 and 3), may lead to confusion in differentiating macroamylasemia from other causes of hyperamylasemia.