In general, serum lipase is thought to be more sensitive and specific than serum amylase in the diagnosis of acute pancreatitis""Although amylase is widely available and provides acceptable accuracy of diagnosis, where lipase is available it is preferred for the diagnosis of acute pancreatitis (recommendation grade A)"Most, but not all individual studies support the superiority of the lipase. In one large study, there were no patients with pancreatitis who had an elevated amylase with a normal lipase. Another study found that the amylase could add diagnostic value to the lipase, but only if the results of the two tests were combined with a discriminant function equation.While often quoted lipase levels of 3 or more times the upper-limit of normal is diagnostic of pancreatitis, there are also other differential diagnosis to be considered relating to this rise. Computed tomography
Regarding the need for computed tomography, practice guidelines state:
CT is an important common initial assessment tool for acute pancreatitis.
It is recommended that APACHE-II scores be generated during the first 3 days of hospitalization and thereafter as needed to help in this distinction. It is also recommended that serum hematocrit be obtained at admission, 12 h after admission, and 24 h after admission to help gauge adequacy of fluid resuscitation. "2005: "Immediate assessment should include clinical evaluation, particularly of any cardiovascular, respiratory, and renal compromise, body mass index, chest x ray, and APACHE II score"

Ranson score
The Ranson score is used to predict the severity of acute pancreatitis. They were introduced in 1974. At admission
age in years > 55 years
white blood cell count > 16000 cells/mm3
blood glucose > 11.1 mmol/L (> 200 mg/dL)
serum AST > 250 IU/L
serum LDH > 350 IU/L

At 48 hours
Calcium (serum calcium < 2.0 mmol/L (< 8.0 mg/dL)
Hematocrit fall >10%
Oxygen (hypoxemia PO2 < 60 mmHg)
BUN increased by 1.8 or more mmol/L (5 or more mg/dL) after IV fluid hydration
Base deficit (negative base excess) > 4 mEq/L
Sequestration of fluids > 6 LThe criteria for point assignment is that a certain breakpoint be met at any time during that 48 hour period, so that in some situations it can be calculated shortly after admission. It is applicable to both gallstone and alcoholic pancreatitis. Alternatively, pancreatitis can be diagnosed by meeting any of the following:[2]

Alternative Ranson score
Ransons score of ≥ 8
Organ failure
Substantial pancreatic necrosis (at least 30% glandular necrosis according to contrast-enhanced CT)
Interpretation
If the score ≥ 3, severe pancreatitis likely.