Serum amylase and lipase concentrations and lipase/amylase ratio in assessment of etiology and severity of acute pancreatitis.

We studied the behavior of serum amylase and lipase in 66 consecutive patients with acute pancreatitis in order to assess the ability of these tests and of the serum lipase-amylase ratio to establish the etiology and predict the severity of acute pancreatitis. Forty-two patients had biliary acute pancreatitis, 14 had alcoholic acute pancreatitis, and the remaining 10 nonbiliary, nonalcoholic (NBNA) acute pancreatitis. Serum amylase and lipase were abnormally high in all patients. The elevations of both serum amylase and lipase were significantly lower in patients with alcoholic pancreatitis than in those with biliary pancreatitis, although a considerable overlap was observed between the two groups. No statistically significant differences were found between NBNA patients and those with either biliary or alcoholic forms of the disease. The serum lipase-amylase ratios in patients with alcoholic pancreatitis ranged from 0.2 to 5.6, in those with biliary pancreatitis from 0.1 to 7.9, and in those with NBNA pancreatitis from 0.1 to 4.4. These differences were not statistically significant. No differences in serum enzyme levels were observed among patients without apparent imaging signs of acute pancreatitis (N = 20), those with signs of pancreatic edema (N = 36), and those with necrotizing pancreatitis (N = 10). The results indicate that serum amylase and lipase concentrations are not able to establish either the etiology or to predict the severity of acute pancreatitis as assessed by imaging techniques. Furthermore, the serum lipase-amylase ratio is not useful in distinguishing acute episodes of alcoholic from nonalcoholic acute pancreatitis.