Serum exchangeable copper (EC) and relative exchangeable copper (REC) are blood tests developed to improve the assessment of copper levels in patients with Wilson's disease. EC measures the fraction of copper in the blood that is not bound to ceruloplasmin and reflects copper accumulation in the body. REC represents the proportion of this exchangeable copper relative to total serum copper. Previous studies have shown that EC and REC are more accurate than traditional copper tests for diagnosing Wilson's disease. This study aimed to evaluate the relationship between EC/REC and routine copper measurements in patients with Wilson's disease during follow-up, to assess their potential value in disease monitoring.
Wilson's disease (WD) is an inherited disorder of copper metabolism caused by mutations in the ATP7B gene and transmitted in an autosomal recessive manner. The disease leads to progressive copper accumulation in multiple organs, particularly the liver and brain, resulting in a wide spectrum of clinical manifestations, including hepatic, neurological, and psychiatric involvement. Accurate monitoring of copper levels is essential for evaluating treatment response and adjusting therapy in patients with WD. In routine clinical practice, copper status is commonly assessed using 24-hour urinary copper excretion and non-ceruloplasmin-bound copper. However, these traditional measurements have important limitations. Collection of 24-hour urine samples is cumbersome and prone to errors, and interpretation may be challenging in patients with renal dysfunction or neurological involvement. Total serum copper reflects both ceruloplasmin-bound and non-ceruloplasmin-bound copper. In WD, despite increased total body copper, serum ceruloplasmin levels are reduced, leading to low ceruloplasmin-bound copper concentrations. As a result, total serum copper measurements may not reliably reflect copper overload. Non-ceruloplasmin-bound copper is calculated indirectly by subtracting ceruloplasmin-bound copper from total serum copper and depends on accurate ceruloplasmin measurement. Immunological assays may overestimate ceruloplasmin levels, resulting in unreliable or even negative calculated values. Serum exchangeable copper (EC) and relative exchangeable copper (REC) have been developed to address these limitations. EC represents the directly measured fraction of serum copper that is not bound to ceruloplasmin and is thought to better reflect bioavailable and tissue copper accumulation. REC is calculated as the ratio of EC to total serum copper. Previous studies have shown that EC and REC are more sensitive and specific than conventional copper tests and have been validated for the diagnosis of WD. However, their role as biomarkers in the follow-up and management of patients with WD has not been fully established. The aim of this study was to evaluate the relationship between EC and REC and routine copper measurements in adult patients with Wilson's disease during follow-up, in order to assess their potential utility in monitoring copper status.
Study Type
OBSERVATIONAL
Enrollment
81
Hacettepe Üniversitesi İç Hastalıkları Anabilim Dalı
Ankara, Sıhhıye, Turkey (Türkiye)
Correlation Between Serum Exchangeable Copper and 24-hour Urinary Copper Excretion in Wilson's Disease
Correlation coefficient (r) between serum exchangeable copper (EC) concentration (µmol/L), measured by inductively coupled plasma mass spectrometry (ICP-MS), and 24-hour urinary copper excretion (µg/24 h), measured by atomic absorption spectrometry, in adult patients with Wilson's disease
Time frame: Day 1
Correlation Between Serum Exchangeable Copper and Total Serum Copper in Wilson's Disease and Controls
Correlation coefficient (r) between serum exchangeable copper (EC) concentration (µmol/L) and total serum copper concentration (µmol/L), both measured by inductively coupled plasma mass spectrometry (ICP-MS), in adult patients with Wilson's disease and age- and sex-matched control participants
Time frame: Day 1
Assessment of Correlation Between Relative Exchangeable Copper and Urinary Copper Excretion in Wilson's Disease
Correlation coefficient (r) between relative exchangeable copper (REC, %) and 24-hour urinary copper excretion (µg/24 h), measured by atomic absorption spectrometry, in adult patients with Wilson's disease
Time frame: Day 1
Difference in serum exchangeable copper (EC) between Wilson's disease patients and controls
Comparison of serum exchangeable copper (EC) levels between adult patients with Wilson's disease and age- and sex-matched control participants.
Time frame: Day 1
Difference in relative exchangeable copper (REC) between Wilson's disease patients and controls
Comparison of relative exchangeable copper (REC) levels between adult patients with Wilson's disease and age- and sex-matched control participants.
Time frame: Day 1
Difference in total serum copper between Wilson's disease patients and controls
Comparison of total serum copper levels between adult patients with Wilson's disease and age- and sex-matched control participants.
Time frame: Day 1
Comparison of 24-hour urinary copper excretion by Disease Phenotype in Wilson's Disease
Comparison of 24-hour urinary copper excretion (µg/day) between adult patients with hepatic involvement and those with hepatic-neurologic involvement in Wilson's disease.
Time frame: Day 1
Comparison of Serum Exchangeable Copper by Disease Phenotype in Wilson's Disease
Comparison of serum exchangeable copper (EC, µmol/L) between patients with hepatic involvement and those with hepatic-neurologic involvement, in adult patients with Wilson's disease.
Time frame: Day 1
Comparison of Relative Exchangeable Copper by Disease Phenotype in Wilson's Disease
Comparison of relative exchangeable copper (REC, %), between patients with hepatic involvement and those with hepatic-neurologic involvement, in adult patients with Wilson's disease.
Time frame: Day 1
Comparison of Total Serum Copper by Disease Phenotype in Wilson's Disease
Comparison of total serum copper concentration (µmol/L), between patients with hepatic involvement and those with hepatic-neurologic involvement, in adult patients with Wilson's disease.
Time frame: Day 1
Comparison of Copper Tests by Chelator Treatment in Wilson's Disease
Differences in 24-hour urinary copper excretion (µg/day), serum exchangeable copper (EC, µmol/L), relative exchangeable copper (REC, %), and total serum copper concentration (µmol/L) between patients treated with penicillamine and those treated with trientine, in adult patients with Wilson's disease
Time frame: Day 1
Correlation of 24-Hour Urinary Copper Excretion With Ceruloplasmin and Routine Laboratory Parameters in Wilson's Disease
Correlation coefficient (r) between 24-hour urinary copper excretion (µg/day) and serum ceruloplasmin levels and selected routine laboratory parameters (including liver enzymes, bilirubin, albumin, and blood cell counts) in adult patients with Wilson's disease.
Time frame: Day 1
Correlation of Serum Exchangeable Copper With Ceruloplasmin and Routine Laboratory Parameters in Wilson Disease
Correlation coefficient (r) between serum exchangeable copper (EC, µmol/L) and serum ceruloplasmin levels and selected routine laboratory parameters (including liver enzymes, bilirubin, albumin, and blood cell counts) in adult patients with Wilson's disease.
Time frame: Day 1
Correlation of Relative Exchangeable Copper With Ceruloplasmin and Routine Laboratory Parameters in Wilson Disease
Correlation coefficient (r) between relative exchangeable copper (REC, %) and serum ceruloplasmin levels and selected routine laboratory parameters (including liver enzymes, bilirubin, albumin, and blood cell counts) in adult patients with Wilson's disease.
Time frame: Day 1
Correlation of Total Serum Copper Concentration With Ceruloplasmin and Routine Laboratory Parameters in Wilson Disease
Correlation coefficient (r) between total serum copper concentration (µmol/L) and serum ceruloplasmin levels and selected routine laboratory parameters (including liver enzymes, bilirubin, albumin, and blood cell counts) in adult patients with Wilson's disease.
Time frame: Day 1
Distribution of Urinary Copper Excretion Categories in Wilson's Disease
Proportion of adult patients with Wilson's disease classified as having low, on-target, or high 24-hour urinary copper excretion according to treatment-specific target ranges
Time frame: Day 1
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