It is scored through the mnemonic, PANCREAS:

P - PaO2 <8kPa
A - Age >55-years-old
N - Neutrophilia: WCC >15x10(9)/L
C - Calcium <2 mmol/L
R - Renal function: Urea >16 mmol/L
E - Enzymes: LDH >600iu/L; AST >200iu/L
A - Albumin <32g/L (serum)
S - Sugar: blood glucose >10 mmol/L

BISAP score
Predicts mortality risk in pancreatitis with fewer variables than Ransons criteria. Data should be taken from the first 24 hours of the patients evaluation. BUN >25 mg/dL (8.9 mmol/L)
Abnormal mental status with a Glasgow coma score <15
Evidence of SIRS (systemic inflammatory response syndrome)
Patient age >60 years old
Imaging study reveals pleural effusionPatients with a score of zero had a mortality of less than one percent, whereas patients with a score of five had a mortality rate of 22 percent. In the validation cohort, the BISAP score had similar test performance characteristics for predicting mortality as the APACHE II score. As is a problem with many of the other scoring systems, the BISAP has not been validated for predicting outcomes such as length of hospital stay, need for ICU care, or need for intervention. Epidemiology
In the United States, the annual incidence is 18 cases of acute pancreatitis per 100,000 population, and it accounts for 220,000 hospitalizations in the US. In a European cross-sectional study, incidence of acute pancreatitis increased from 12.4 to 15.9 per 100,000 annually from 1985 to 1995; however, mortality remained stable as a result of better outcomes.
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.