Lactate levels provide additional prognostic value beyond existing scoring systems for predicting mortality in critically ill cirrhotic patients. A multinational study assessed lactate levels and lactate clearance in 584 ICU patients with cirrhosis. Lactate levels on admission were associated with increased short and long-term mortality. The study derived a modified CLIF-C ACLF score incorporating lactate (CLIF-C ACLFsLact) that showed improved discrimination for predicting 28-day, 90-day, and 1-year mortality compared to the original CLIF-C ACLF score or MELD score. The CLIF-C ACLFsLact also showed better prediction of mortality in a validation cohort of 250 patients.