Diagnostic use of pancreatic lipase determination by radial enzyme diffusion, and design of a routine pancreatic profile.

The differential diagnosis of diseases of the pancreas remains an acute problem area in medicine today. It can be stated with some certainty that no single test has the capability of 100% accuracy in the diagnosis of pancreatic disease, much less in the determination of the etiology of the condition. Basically, from the viewpoint of the clinical laboratory, inflammatory diseases of the pancreas can be placed in three broad categories: (a) acute, (b) chronic end stage, and (c) those cases that fall between a and b, including subacute pancreatitis, chronic relapsing pancreatitis, and space-occupying lesions of the pancreas. In addition, each group can be subdivided into obstructive and nonobstructive diseases and further subdivided into those with involvement of the common duct or simple pancreatic obstruction. Various tests have been proposed to differentiate these conditions, but each measures a different metabolic aspect of the patient’s physiology. Serum amylase activity is perhaps the most widely used and accepted index to pancreatic function. However, amylase is produced by several organs including pancreas, salivary glands, liver and kidney, and so an abnormally high value for serum amylase is only consistent with, but not diagnostic for, acute pancreatitis. An additional complication in the interpretation of serum amylase values is the kidney function of the patient. Amylase is excreted in the urine and, as such, the renal status of the patient can greatly influence its activity in serum and urine. Warshaw and Fuller (1) have proposed normalizing the amylase clearance rate to the creatinine clearance rate. Our experience with this clearance ratio will be discussed.