Has Amylase Become Obsolete?

Amylases are a group of hydrolases that degrade complex carbohydrates into glucose subunits.  The exocrine pancreas and salivary glands produce amylase to facilitate starch digestion.

Serum amylase levels become elevated in patients with pancreatitis. Many disease states other than pancreatitis can increase serum amylase levels including; perforated ulcers, intestinal obstruction, mesenteric infarction, ectopic pregnancy, biliary tract disease, acute alcohol intoxication, diabetic ketoacidosis, liver metastases, duodenitis, abdominal trauma, head trauma, thoracic surgery, and genitourinary disorders.   Renal failure is also associated with elevated serum amylase because renal filtration normally accounts for about 25% of its clearance. 

The American College of Gastroenterology practice guidelines suggest that measuring both serum amylase and lipase is not necessary to diagnose pancreatitis. Serum lipase alone is the preferred test because it is more sensitive, just as specific, increases sooner and remains elevated longer than amylase. The sensitivity of serum lipase is 91 to 96%, and the sensitivity of amylase is 62 to 74%. The specificity of both tests is 92 to 99%.

A recent article from the Cleveland Clinic reviewed the results of 26,254 orders for serum amylase and lipase in 13,198 patients between 2011 and 2014. In 9938 of the patients, both tests were ordered concurrently. Of these patients, 482 (4.8%) had either amylase or lipase elevated more than 3 times the upper limit of normal and 63 of the 482 patients had a similar elevation in serum amylase alone. None of the patients with elevation of amylase alone had acute pancreatitis. The authors concluded that serum amylase testing is unnecessary.

Cleveland Clinic has introduced a best practice alert in their computerized order entry system that cautions physicians that ordering both serum amylase and lipase in cases of suspected pancreatitis is unnecessary. They are now considering eliminating serum amylase testing altogether.

References

Akhtar A. et al. Measuring both serum amylase and lipase for acute pancreatitis lowers quality and raises cost. Cleveland Clinic J Medicine. September 2017;84(9)670-672.

Banks PA, Freeman ML. Practice Parameters Committee of the American College of Gastroenterology. Practice guidelines in acute pancreatitis. Am J Gastroenterol 2006;101:2379-2400

AddThis Social Bookmark Button