Serum lipase should be the laboratory test of choice for suspected acute pancreatitis

Background. Serum lipase and amylase are biochemical analyses used to establish the diagnosis of acute pancreatitis (AP). Despite lipase having been shown internationally to be a more sensitive and specific test, amylase remains a popular first-line test. Objective. To provide a local basis for the recommendation of the best first-line laboratory test, an assessment of their performance in our local setting was undertaken. Methods. From a prospective dataset on patients with acute abdominal pain and raised serum lipase and/or amylase values, the sensitivity and specificity of serum lipase, amylase and the two in combination was calculated for the diagnosis of AP, as defined by the Atlanta criteria. Results. During the study period, 476 patients presented with acute upper or generalised abdominal pain and raised serum amylase and/or lipase values. The median age of the patients was 43 years (range 14 - 85), and 58% were men and 42% women. Of the patients, 322 (68%) presented with abdominal conditions other than AP, and 154 (32%) had AP. Ethanol abuse and gallstones accounted for 55% and 23% of cases of AP, respectively. Lipase displayed a sensitivity of 91% for AP, against 62% for amylase. Specificity was 92% for lipase and 93% for amylase. Dual testing with lipase and amylase had a sensitivity of 93%. Conclusions. Lipase is a more sensitive test than amylase when utilising cut-off levels to diagnose AP. Lipase should replace amylase as the first-line laboratory investigation for suspected AP.