Performance of Relative Exchangeable Copper for the Diagnosis of Wilson Disease in Acute Liver Failure

Acute liver failure (ALF) can be one of the manifestations of Wilson disease (WD), and due to its severity, prompt diagnosis is essential. A ratio > 15% of the exchangeable copper to total serum copper, known as relative exchangeable copper (REC), has been shown to have a 100% sensitivity and specificity for the diagnosis of WD but this has not yet been studied in an ALF setting. Patients diagnosed with ALF from 1 November 2011 to 31 December 2023, with available REC determination during the acute event, were included. Thirty-three patients were included (11 with WD and 22 without WD). The median age [IQR] at ALF was 12.9 [8.9–20.2] years, range: 0.6–71.0 years. Serum ceruloplasmin (Cp) < 0.20 g/L and 24 h urinary copper excretion > 1.6 μmol/L had both a sensitivity (Se) and specificity (Sp) for the diagnosis of WD of 100% and 72.7%, respectively. A ROC analysis of REC determined that the best cut-off point was 14.4% (AUC 1, p < 0.01). All the WD patients had REC values > 14.4%, yielding a sensitivity and specificity of 100. Relative exchangeable copper has 100% sensitivity and specificity for diagnosing Wilson disease in acute liver failure. Relative exchangeable copper has excellent performance in diagnosing Wilson disease in acute liver failure.