The value of six prognostic markers was assessed prospectively in 198 attacks of acute pancreatitis with specific attention to their ability to predict pancreatic necrosis. The Imrie Prognostic Score (IPS) was recorded within 48 h of diagnosis. The serum C-reactive protein (CRP) alpha 1 antiprotease (A1AP), alpha 2 macroglobulin (A2M), amylase and white cell count (WCC) were measured on days 1, 3 and 7. When comparing all severe clinical outcomes to mile outcomes, serum CRP concentrations were higher on all three days (P less than 0.02, less than 0.001, less than 0.001), A1AP concentrations were higher on day 3 (P less than 0.05), A2M concentrations were lower on day 7 (P less than 0.01) and WCC was higher on all three days (P less than 0.001, less than 0.001, less than 0.001). Serum amylase concentrations showed no significant differences. None of the measured parameters were helpful in distinguishing patients who subsequently developed pancreatic necrosis from patients who had other severe outcomes. Multivariate analysis revealed that the initial IPS showed greatest independent significance in predicting severe outcome followed by the WCC (days 1 and 7) and CRP (day 3). CRP and WCC may be clinically useful predictors of severe outcome to supplement the initial IPS. These methods are unlikely to distinguish pancreatic necrosis from other severe outcomes, but they may supplement clinical judgment in selecting a high risk group of patients for contrast enhanced computed tomography.