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 Cam/Ccr-ratios were determined 14 times in the 3 macroamylasemic patients. Only one of the 14 values was clearly less than 1%. Cam/Ccr-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 Cam/Ccr-ratios below 4%. Cam/Ccr-ratios below 1% were also found in patients without macroamylasemia. It is concluded that high and low Cam/Ccr-ratios are not specific for acute pancreatitis and macroamylasemia, respectively, and--moreover--that a normal Cam/Ccr-ratio excludes neither acute pancreatitis nor macroamylesemia.

Amylase/Creatinine Clearance Ratio and Tubular Proteinuria in Acute Pancreatitis

“…While some confirmed the value of this investigation (2 -5 ), others demonstrated that a normal CAm/CCr does not exclude acute pancreatitis (6 -8 ) as has been previously sug gested (9). Furthermore, other groups question the specificity of the CAm/Ccr> reporting raised values in several conditions other than pancre atitis: bums and ketoacidosis (10), acute duo denal perforation (11), renal insufficiency (6,8,(12)(13)(14) and thoracic operation (15,16).…”

Macroamylasemia: A Biochemical or Clinical Problem?

“…An amylase clearance/creatinine clear ance (Cam/Ccr) ratio below 1 % would strengthen suspicion of underlying macro amylasemia [44], Indeed, the inability of macrocomplexes to pass through the glomerular filter induces a low Cam/Ccr ratio, at least in Type 1. However, Cam/Ccr failed to be sensitive and specific in many conditions [45], So, a Cam/Ccr below 1 % may be observed in the case o f 'S-type hyperamylasemia' [46].…”