Evaluation of amylase and lipase in the diagnosis of acute pancreatitis.
BACKGROUND
The diagnosis of acute pancreatitis relies heavily on a raised amylase.


METHODS
In the present study patients were prospectively categorized, without knowledge of pancreatic enzyme levels, into acute pancreatitis (AP; n = 51), disease controls (n = 35), indeterminate as to pancreatitis (n = 189) or exclusions (non-pancreatitis diseases where amylase may be elevated; n = 53).


RESULTS
Enzyme levels were analysed by receiver operator characteristics (ROC) curves, with specificity > 80%. Day 1 serum lipase gave the greatest diagnostic accuracy (area under ROC curve = 0.128; P = 0.041 vs serum amylase). At the calculated diagnostic threshold of 208 U/L, lipase gave a sensitivity of 67% and a specificity of 97%. Other diagnostic thresholds (day 1) were: serum total amylase, 176 U/L (ROC 0.104, sensitivity 45%, specificity 97%), urinary total amylase, 550 U/L (ROC 0.108, sensitivity 62%, specificity 97%) and serum pancreatic isoamylase, 41 U/L (ROC 0.107, sensitivity 63%, specificity 85%). At delayed diagnosis (3 days) no enzyme was superior to lipase. The combination of lipase and amylase did not increase diagnostic accuracy.


CONCLUSIONS
Serum lipase is recommended for diagnosis of AP, both early and late in the disease. Although highly specific when elevated, all pancreatic enzymes have low sensitivity for diagnosis.
Treacy
J
J
Hepato-Biliary and Pancreatic Surgical Unit, Royal Adelaide Hospital, Flinders University of South Australia (Northern Territory Clinical School), Adelaide, South Australia, Australia. john.treacy@nt.gov.au
Williams
A
A
Bais
R
R
Willson
K
K
Worthley
C
C
Reece
J
J
Bessell
J
J
Thomas
D
D
D000208:Acute Disease; D000681:Amylases / Q000097:blood*; D004796:Clinical Enzyme Tests; D006801:Humans; D008049:Lipase / Q000097:blood*; D010179:Pancreas / Q000201:enzymology*; D010195:Pancreatitis / Q000175:diagnosis*; D012372:ROC Curve; D012680:Sensitivity and Specificity
D008049:Lipase; D000681:Amylases