Serum levels of six pancreatic enzymes as related to the degree of renal dysfunction.

OBJECTIVES

Currently, serum total amylase, pancreatic isoamylase (P-amylase), lipase, trypsin(ogen), phospholipase A2 (PLA2), and elastase I are advocated to be useful in diagnosing pancreatic diseases. However, the most useful among the above six enzymes in patients with impaired renal function has not been fully clarified. We, therefore, studied the relation of the serum levels of the above enzymes and creatinine clearance (CrCl) in normal controls and patients with chronic renal insufficiency or failure.

METHODS

PLA2 and elastase I were assayed by RIA, trypsin(ogen) by EIA and others by activity. Subjects were 24 healthy controls and 47 patients with impaired renal function and no apparent pancreatic diseases.

RESULTS

1. Elastase I was significantly elevated only in patients with a CrCl of 10 ml/min or less, whereas others were elevated already in patients with a CrCl below 40 ml/min; 2) in 12 patients with a CrCl between 13 and 39 ml/min, lipase tended to be less frequently raised than others, except elastase I, although the difference was statistically insignificant; 3) in 28 patients with a CrCl between 40 and 74 ml/min, lipase was less frequently elevated than others, except elastase I and PLA2; 4) in seven patients with a CrCl of 10 ml/min or below, elastase I tended to be less frequently elevated than others, although the difference was statistically insignificant; and 5) the degree of elevation was within 2.5 times the upper limits of reference values in all enzymes, except trypsin(ogen) (within 4.8 times).

CONCLUSIONS

Elastase I was least vulnerable to impaired renal function followed by lipase. We, therefore, recommend combined assays of elastase I and lipase for detecting pancreatic diseases in patients with renal insufficiency. When cut-off levels are set at 2.5 times the upper limit of reference values, P-amylase or PLA2 can replace lipase.