Usefulness of penicillamine-stimulated urinary copper excretion in the diagnosis of adult Wilson's disease

Abstract

Objective. Diagnosis of Wilson's disease (WD) is reliant on liver biopsy (LB) and measurement of hepatic copper. The aim of this study was to determine the usefulness of penicillamine-stimulated urinary copper excretion (PS-UCE), a non-invasive diagnostic test, for the diagnosis of WD in adults. Material and methods. In this prospective study of patients with suspected WD, total serum copper, ceruloplasmin, basal 24-h UCE and PS-UCE levels were measured. LB with copper determination was performed in those patients with persistent hypertransaminasemia and low ceruloplasmin or basal UCE >40 µg/24 h. Diagnosis was established if the ceruloplasmin level was found to be <20 mg/dl and hepatic copper >250 µg/g. Results. A total of 115 patients were studied; LB was performed in 43, and WD was diagnosed in 6 (13.9%). Significant differences between WD and non-WD patients were found for basal UCE (WD: median 134.3 µg/24 h versus non-WD: median 19.0 µg/24 h (p<0.05)) and PS-UCE (WD: median 1284.0 µg/24 h versus non-WD: median 776.0 µg/24 h; p<0.01). In the ROC (receiver-operated curve) analysis, PS-UCE was the best discriminant between WD and non-WD (area under the curve (AUC)=0.911, best cut-off point 1057 µg/24 h, 100% sensitivity, 82.3% specificity). Conclusions. PS-UCE is probably a useful non-invasive test in the diagnosis of WD, improving the selection of patients for diagnostic liver biopsy. Patients with PS-UCE under 1057 µg/24 h only rarely will suffer from WD and are unlikely to benefit from LB.

• Diagnosis
• penicillamine
• Wilson's disease