n South African Journal of Surgery - Serum lipase should be the laboratory test of choice for suspected acute pancreatitis : general surgery

Abstract

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.

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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.

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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.

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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%.

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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.