The authors assessed the clinical and prognostic value of abdominal (ASCI) and pulmonary (PSCI) scintiscans with 111Indium-labelled leukocytes in the early phase of acute pancreatitis. A grading scale was constructed for both ASCI (scored 0 to 3) and PSCI (scored 0 to 2) according to the intensity of isotope fixation versus adjacent structures. Results were compared in accordance to the presence or absence of a Ranson's score greater than or equal to 3, the presence or absence of respiratory failure and of late pancreatic complications. ASCI showed an important lack of specificity making its use uninteresting. PSCI revealed a very significant correlation with evaluation by Ranson's score and appears to have a high sensitivity and specificity to evaluate the patients who will develop ARDS or risk of ARDS. This demonstrates the pathophysiological role of leukocytes in the early phase of severe acute pancreatitis. The test might also be a reliable test for the assessment of therapeutic efficiency in acute pancreatitis.