Fractional urinary clearance of immunoreactive lipase in chronic pancreatic disease.

Using an immunoenzymatic method, we studied lipase in the serum and urine of 23 controls, 22 chronic pancreatitis patients in symptomatic remission, and in 9 patients with proven pancreatic cancer. Serum and urine lipase and its fractional urinary clearance were compared with those of amylase and immunoreactive trypsin. Lipase immunoreactivity was detectable in the urine of 81.5% of the studied subjects (controls: 82%, chronic pancreatitis: 86%, pancreatic cancer: 66%); its output was higher than the upper limit of controls in 31.8% of chronic pancreatitis and in only 1 of pancreatic cancer, and it was significantly correlated with the urinary output of trypsin (r = 0.487, P less than 0.001), but not with that of amylase. A significant correlation was found between urinary output and serum levels for lipase, but not for trypsin or amylase. Fractional clearance of lipase was of the same magnitude as that of trypsin but only 0.1% that of amylase. 19% of chronic pancreatitis and pancreatic cancer showed a fractional clearance of lipase above the upper limit of controls, compared with 45% for trypsin and 3.2% for amylase. No difference in urinary clearance of the three enzymes was found between chronic pancreatitis and pancreatic cancer. In conclusion, although of no diagnostic relevance in pain-free patients with chronic pancreatic disease, this measurement can provide information on the mechanisms of renal excretion of pancreatic enzymes.