The 24-hour urine copper excretion (UCE) test is indicated for the diagnosis of Wilson disease (WD). It might be a valuable measure for assessing therapy efficacy during follow-up; however, there is insufficient evidence on the cutoff value of 24-hour UCE during follow-up in children. As a result, the researchers wanted to assess the clinical utility of 24-hour UCE during follow-up in children with WD. Medical data of children diagnosed with WD at Kings’ College Hospital were reviewed retrospectively. During the follow-up, the UCE, serum copper, and ceruloplasmin levels were statistically evaluated. During the median follow-up period of 7 years, 28 patients underwent UCE testing. Twenty-one individuals received at least one 24-hour UCE test, whereas seven children had just spot UCE testing. In comparison to the level of 24-hour UCE collected at the first visit following the penicillamine challenge test, the median excretion rate decreased significantly over the follow-up period, from 26.2 to 8.9 mol/day after 1–2 years of therapy, then to 2.2 mol/day after 3–4 years, and to 5.6 mol/day after >5 years of follow-up.

According to the study, after one year of therapy, the amount of nonceruloplasmin-bound copper concentration declines to 0.8 mol/L. In the absence of increasing liver disease or indications of copper shortage, the 24-hour UCE drops to 8 mol/day and 6 mol/day, respectively.

Reference: https://journals.lww.com/jpgn/Abstract/2021/02000/Long_Term_Urinary_Copper_Excretion_on_Chelation.7.aspx

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