Background Wilson's disease is a rare cause of acute liver failure and is highly fatal without liver transplantation. Fast and accurate diagnostic methods are needed for fulminant Wilson's disease (FWD). In this study, we aimed to develop an early, simple and accurate diagnostic method to differentiate FWD from nonwilsonian acute liver failure (NWALF) causes using routine biochemical data. Methods The medical records of 24 paediatric FWD and 120 paediatric NWALF cases diagnosed at the Department of Pediatric Gastroenterology, Hepatology, and Nutrition between January 2007 and February 2017 were retrospectively reviewed. Results Using receiver operator characteristics curve (ROC) analysis, we have determined the best cut-off point for laboratory findings in FWD. Patients meeting these cut-off points were assigned one point and others were assigned zero point. We then formed a new variable consisting of the combination of 14 variables and performed a new ROC analysis. We obtained a cut-off point of >= 4.5 for FWD. The diagnostic performance of the score was characterized by a sensitivity of 0.889, a specificity of 0.879 (P < .001). A scoring system based only on aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase, AST/ALT ratio, uric acid and haemoglobin had a best cut-off point of >= 2.5 for FWD, which had a sensitivity of 0.875, a specificity of 0.867 (P < .001). Conclusions Our study demonstrated that biochemical markers offer almost as reliable, fast and accurate diagnosis of FWD as offered by ceruloplasmin and 24-hour urinary copper.