Retrospective study of patients with acute pancreatitis: is serum amylase still required?

BMJ Open. 2012 Sep 21;2(5):e001471. doi: 10.1136/bmjopen-2012-001471. Print 2012.

Abstract

Objectives: To assess the role of serum amylase and lipase in the diagnosis of acute pancreatitis. Secondary aims were to perform a cost analysis of these enzyme assays in patients admitted to the surgical admissions unit.

Design: Cohort study.

Setting: Secondary care.

Participants: Patients admitted with pancreatitis to the acute surgical admissions unit from January to December 2010 were included in the study.

Methods: Data collated included demographics, laboratory results and aetiology. The cost of measuring a single enzyme assay was £0.69 and both assays were £0.99.

Results: Of the 151 patients included, 117 patients had acute pancreatitis with gallstones (n=51) as the most common cause. The majority of patients with acute pancreatitis had raised levels of both amylase and lipase. Raised lipase levels only were observed in additional 12% and 23% of patients with gallstone-induced and alcohol-induced pancreatitis, respectively. Overall, raised lipase levels were seen in between 95% and 100% of patients depending on aetiology. Sensitivity and specificity of lipase in the diagnosis of acute pancreatitis was 96.6% and 99.4%, respectively. In contrast, the sensitivity and specificity of amylase in diagnosing acute pancreatitis were 78.6% and 99.1%, respectively. Single lipase assay in all patients presenting with abdominal pain to the surgical admission unit would result in a potential saving of £893.70/year.

Conclusions: Determining serum lipase level alone is sufficient to diagnose acute pancreatitis and substantial savings can be made if measured alone.