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

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.