Serum pancreatic isoamylase activity in pancreatic disease.

The diagnostic value of serum amylase determination for pancreatic disease has been questioned due to its lack of specificity. Several methods have been developed to separate the tissue-unspecific salivary fractions from the tissue-specific pancreatic fractions. Agarose or cellulose acetate gel electrophoresis are most suitable for clinical practice. The isoamylase patterns were studied by agarose electrophoresis in 55 patients with known pancreatic diseases (acute pancreatitis, pancreatic pseudocysts, exocrine pancreatic insufficiency and pancreatic carcinoma). Increased P-type isoamylase seems to be more sensitive than total amylase in diagnosing acute pancreatitis, while identification of the minor isoamylase P3 is more specific and could have a prognostic value. Detection of low P-type isoamylase levels is an easy method to diagnose exocrine pancreatic insufficiency. Furthermore, a group of patients with pancreatic disease (Pa), was compared with a group of patients with biliary disease without clinical evidence of pancreatic involvement (Bi), and patients with abdominal pain, without evidence of biliary or pancreatic disease (Ab). More than half of the Bi patients presented with abnormal P isoenzyme patterns, whereas 72% of the Ab patients had a normal pattern. Only P3 could distinguish between the Bi and Ab group. This might point to pancreatic involvement in patients presenting with biliary disease, only detected by isoamylase analysis.