The Frequency of Macroamylasemia and the Diagnostic Value of the Amylase to Creatinine Clearance Ratio in Patients with Elevated Serum Amylase Activity

Abstract

190 patients with elevated serum amylase levels were tested for macroamylasemia and the amylase to creatinine clearance ratio. Macroamylasemia was found in 3 patients. In these patients macroamylasemia persisted after the total activity of serum amylase had fallen to nearly normal levels. The C_am/C_cr-ratios were determined 14 times in the 3 macroamylasemic patients. Only one of the 14 values was clearly less than 1%. C_am/C_cr-ratios above 4% were found in 83 patients. In 56 of them the diagnosis of acute pancreatitis could not be confirmed. 19 out of 46 patients with the established diagnosis of acute pancreatitis had C_am/C_cr-ratios below 4%. C_am/C_cr-ratios below 1% were also found in patients without macroamylasemia. It is concluded that high and low C_am/C_cr-ratios are not specific for acute pancreatitis and macroamylasemia. respectively, and—moreover—that a normal C_am/C_cr-ratio excludes neither acute pancreatitis nor macroamylasemia.

Key-words:

• Acute pancreatitis
• amylase clearance
• chronic pancreatitis
• creatinine clearance
• macroamylasemia
• serum amylase activity