Ranson Criteria Calculator

Ranson criteria grade acute pancreatitis by counting adverse findings at two fixed time points, five on admission and six at 48 hours, for a maximum of 11. The admission items describe the initial inflammatory insult: age over 55, white cell count over 16,000 per microliter, glucose over 200 mg/dL, LDH over 350 IU/L and AST over 250 IU/L. The 48-hour items describe systemic consequences. A hematocrit fall of more than 10 points and fluid sequestration over 6 liters mark plasma loss into the retroperitoneum, a BUN rise over 5 mg/dL marks prerenal injury, calcium under 8 mg/dL reflects saponification of peripancreatic fat by liberated fatty acids, PaO2 under 60 mmHg signals early respiratory failure, and a base deficit over 4 mEq/L indicates tissue hypoperfusion. Gallstone pancreatitis uses stricter thresholds: age over 70, white cells over 18,000, glucose over 220, LDH over 400, BUN rise over 2 and sequestration over 4 liters. Interpretation is banded. Zero to 2 criteria corresponds to under 1 percent mortality, 3 to 4 to roughly 15 percent, 5 to 6 to about 40 percent, and 7 or more to mortality historically quoted near 100 percent. Amylase and lipase appear nowhere in the score, because enzyme concentration establishes the diagnosis but does not track severity. The chief limitation is timing: the score cannot be completed until 48 hours have elapsed, which is precisely the window in which aggressive fluid resuscitation changes outcomes, and its mortality figures were derived from 1970s surgical practice and overstate risk under modern critical care.

John H. C. Ranson, a surgeon at New York University and Bellevue Hospital, published the criteria in Surgery, Gynecology and Obstetrics in 1974, in a paper titled Prognostic signs and the role of operative management in acute pancreatitis. He studied 100 consecutive patients, most with alcohol-related disease, examining dozens of clinical and laboratory measurements to identify which ones separated patients who died or required prolonged intensive care from those who recovered uneventfully. Eleven survived that statistical selection. Ranson later published a modified set with different thresholds for gallstone pancreatitis, since biliary disease produced a different laboratory pattern. Alternatives appeared almost immediately. Clement Imrie and colleagues in Glasgow published a simplified factor-based score in 1978, known since as the Glasgow or Imrie criteria, and APACHE II, introduced by William Knaus and colleagues in 1985, could be recalculated daily instead of being fixed at 48 hours. Bechien Wu and colleagues derived the five-variable BISAP score in 2008 specifically to allow stratification within the first 24 hours. Meanwhile the 1992 Atlanta symposium and its 2012 revision reframed severity around persistent organ failure lasting more than 48 hours and the presence of local complications rather than a count of criteria, so the Ranson score now functions largely as a teaching framework and a historical benchmark rather than a bedside triage instrument.