Amyloid A (SAA) and procalcitonin (PCT) have been reported as useful indicators of inflammation. Our aim was to assess the utility of SAA and PCT in establishing the severity of acute pancreatitis in comparison to C-reactive protein (CRP): Thirty-one patients with acute pancreatitis enrolled within 24 hr from the onset of pain and 31 healthy subjects were studied. Nineteen patients had mild acute pancreatitis, and 12 had severe pancreatitis. Serum SAA, PCT, and CRP were measured in all subjects at admission and, in acute pancreatitis patients, during the following five days. Patients with acute pancreatitis had serum concentrations of SAA, PCT, and CRP significantly higher (P < 0.001) than those of healthy subjects during the entire study period. Using cutoff values ranging from 240 to 250 mg/liter for SAA, from 0.252 to 0.255 ng/ml for PCT, and from 12.8 to 12.9 mg/dl for CRP, the sensitivity (calculated on patients with severe pancreatitis), the specificity (calculated on patients with mild pancreatitis), and the efficiency (calculated as the percentage of correct classifications) were 76.8%, 69.3%, and 72.4% for SAA; 21.7%, 83.2%, and 58.2% for PCT; and 60.9%, 89.1%, and 77.6% for CRP. In conclusion, the sensitivity of SAA is significantly higher than that of PCT and CRP in assessing the severity of pancreatitis, whereas PCT and CRP had a specificity significantly higher than SAA. The accuracy and efficiency were similar for SAA and CRP, and both these markers had an accuracy and efficiency significantly higher than those of PCT.