Objective        To evaluate the clinical values of the bedside index for severity in acute pancreatitis (BISAP) and Ranson’s criteria in predicting severity and mortality in patients with AP.       Methods        Six hundreds and fifty-two patients with AP

who were admitted into our department from June 2007 to October 2010 were enrolled retrospectively. The receiver-operating curve (ROC) of BISAP and Ranson systems were compared in assessing severity and mortality in these AP patients.       Results        Among these 652 patients

there were 108 cases classified as severe AP

21 cases died (3.2%)

44 cases with BISAP score ≥3 (6.7%)

and 213 cases with Ranson score ≥3 within 48 h hospitalization (32.7%). The area under the receiver-operating curve (AUC) for severity by BISAP and Ranson’s were 0.846 (95%CI 0.808 to 0.883)

and 0.771 (95%CI 0.722 to 0.820) respectively (P0.05). The AUC for mortality by BISAP and Ranson were 0.809 (95%CI 0.699 to 0.920)

and 0.762 (95%CI 0.638 to 0.885) respectively (P0.05).       Conclusion       BISAP score system is a more accurate and dynamic method to early predict severity and mortality in AP than Ranson’s criteria. BISAP is a simple

prompt

economical

and ideal prognosis scoring system in clinical practice.