Acute pancreatitis can be diagnosed by using an algorithm for the pattern of laboratory test findings.
Algorithm
If amylase > 2 times the upper limit of normal, then measure lipase.
If lipase is within normal range, perform isoamylase electropheresis. This will distinguish between macroamylasemia and an increased amylase from an extrapancreatic source (salivary pattern).
If lipase is increased but less than 5 times the upper limit of normal, then measure serum creatinine.
(1) If serum creatinine is increased to more than 2 times the upper limit of normal, then the increases reflect renal insufficiency.
(2) If serum creatinine is less than 2 times the upper limit of normal, then the patient either has late acute pancreatitis or else some other intra-abdominal disorder.
If lipase is increased more than 5 times the upper limit of normal, then acute pancreatitis is present.
Limitations:
• Amylase may not be elevated at presentation and may return quickly to normal.
