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BACKGROUND AND AIMS Wilson Disease (WD) is a complex disease in which diagnosis and long-term metabolic copper control remains challenging. The absence of accurate biomarkers requires the combination of different parameters to ensure copper homeostasis. Exchangeable copper and its ratio (REC) have been suggested as useful biomarkers in this setting. We aimed at introducing these measurements in our real-world cohort of WD patients, and to evaluate their performance and accuracy. METHODS Exchangeable copper and REC were measured in 48 samples of WD patients and 56 samples from control individuals by inductively coupled plasma-mass-spectrometry (ICP-MS). Demographic and clinical characteristics were collected at diagnosis and sample extraction. RESULTS REC was shown to be significantly higher in WD compared to controls and useful for WD identification by using the previously established cutoffs: 71.4% of patients with recent diagnosis had REC ≥18.5% and 95.1% of long-term treated WD had REC ≥14%; only 4 patients presented discordant levels. Moreover, all the control individuals showed REC values <15%. Exchangeable copper was significantly higher in WD patients compared to control individuals and, tended to be reduced among WD patients who were compliant to medication. CONCLUSION Exchangeable copper and REC are useful and easy serum biomarkers that can be used as complementary tests to ensure WD diagnosis (REC) and copper homeostasis (exchangeable copper). The desirable target levels for this last objective still needs to be validated in prospective cohorts. This article is protected by copyright. All rights reserved.