SIRS is a simple clinical score, ranging from 0-4, that utilizes objective, routine clinical parameters (body temperature, heart rate, respiratory rate or arterial carbon dioxide tension and white blood count) that directly reflect the underlying inflammatory response. The persistence of SIRS, defined by the presence of a SIRS score ≥2 at 48 hrs following presentation, has been shown to be significantly associated with the development of OF, pancreatic necrosis and death in patients with AP. Additionally, serum levels of CRP at 48 hours following admission have also been closely correlated with the development of OF.