How is a urinary copper excretion rate used in the diagnosis of Wilson disease?

Updated: Feb 14, 2019
  • Author: Richard K Gilroy, MBBS, FRACP; Chief Editor: Praveen K Roy, MD, AGAF  more...
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Answer

The urinary copper excretion rate is greater than 100 mcg/d (reference range, < 40 mcg/d) in most patients with symptomatic Wilson disease. The rate may also be elevated in other cholestatic liver diseases.

The sensitivity and the specificity of this test are suboptimal for use as a screening test; however, it may be useful to confirm the diagnosis and to evaluate the response to chelation therapy.

In an institutional study of 32 patients treated with d-penicillamine (DPA) with routine follow-up studies, 24-hour urinary copper excretion analysis 48 hours after interruption of chelating therapy was a reliable method to confirm patient compliance. [18] The investigators noted that normalization of copper excretion was observed in 91% of reportedly compliant patients, with an 87% specificity and 77% sensitivity.


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