Isoamylases and their thermolability in serum and cyst fluid from patients with pancreatic pseudocysts.

The isoamylase pattern in serum and the amylase thermolability have been suggested as screening tests for the development of pancreatic pseudocysts. To study whether serum reflects the contents of pseudocysts, we have investigated the isoamylases and their thermolability in cyst fluid and in serum from 13 patients with pancreatic pseudocysts. No significant correlation was found between the contents in serum and cyst fluid with regard to total amylase and isoamylase P2 and P3 or with regard to the thermolability of total amylase and isoamylase P2 and P3. Thus, serum does not reflect the cyst contents of isoamylases or their thermolability. Therefore these serum amylase determinations can hardly be expected to be useful in distinguishing patients developing pseudocysts among patients with pancreatitis.