Sorted By Test Name - Mayo Medical Laboratories

CUS
8612
Clinical Information: The biliary system is the major pathway of copper excretion. Biliary excretion
of copper requires an ATP-dependent transporter protein. Mutations in the gene for the transporter protein
cause hepatolenticular degeneration (Wilson disease). Ceruloplasmin, the primary copper-carrying protein
in the blood, is also reduced in Wilson disease. Urine copper excretion is increased in Wilson disease due
to a decreased serum binding of copper to ceruloplasmin, or due to allelic variances in cellular metal ion
transporters. Hypercupriuria is also found in Menkes disease (kinky hair disease), hemochromatosis,
biliary cirrhosis, thyrotoxicosis, various infections, and a variety of other acute, chronic, and malignant
diseases (including leukemia). Urine copper concentrations are also elevated in patients taking
contraceptives or estrogens and during pregnancy. Low urine copper levels are seen in malnutrition,
hypoproteinemias, malabsorption, and nephrotic syndrome. Increased zinc consumption interferes with
normal copper absorption from the gastrointestinal tract causing hypocupremia.
Useful For: Investigation of Wilson disease and obstructive liver disease
Interpretation: Humans normally excrete 60 mcg/L may be seen in: -Wilson disease -Menkes disease -Obstructive biliary disease (eg, primary
biliary cirrhosis, primary sclerosing cholangitis) -Nephrotic syndrome (due to leakage through the kidney)
-Chelation therapy -Estrogen therapy -Mega-dosing of zinc-containing vitamins Because ceruloplasmin is
an acute phase reactant, urine copper is elevated during acute inflammation. During the recovery phase,
urine copper is usually below normal, reflecting the expected physiologic response to replace the copper
that was depleted during inflammation.
Reference Values:
0-15 years: not established
> or =16 years: 15-60 mcg/L
Clinical References: 1. Zorbas YG, Kakuris KK, Deogenov VA, et al: Copper homeostasis during
hypokinesia in healthy subjects with higher and lower copper consumption. Trace Elements and
Electrolytes 2008;25:169-178 2. Lech T, Sadlik JK: Contribution to the data on copper concentration in
blood and urine in patients with Wilson's disease and in normal subjects. Biol Trace Elem Res 2007
Jul;118(1):16-20
Copper, Serum
Clinical Information: In serum from normal, healthy humans, more than 95% of the copper is
incorporated into ceruloplasmin; the remaining copper is loosely bound to albumin. Low serum copper,
most often due to excess iron or zinc ingestion and infrequently due to dietary copper deficit, results in
severe derangement in growth and impaired erythropoiesis. Low serum copper is also observed in
hepatolenticular degeneration (Wilson disease) due to a decrease in the synthesis of ceruloplasmin and
allelic variances in cellular metal ion transporters. In Wilson disease, the albumin-bound copper may
actually be increased, but ceruloplasmin copper is low, resulting in low serum copper. However, during
the acute phase of Wilson disease (fulminant hepatic failure), ceruloplasmin and copper may be normal;
in this circumstance, hepatic inflammation causes increased release of ceruloplasmin. It is useful to relate
the degree of liver inflammation to the ceruloplasmin and copper-see discussion on hypercupremia below.
Significant hepatic inflammation with normal ceruloplasmin and copper suggest acute Wilson disease.
Other disorders associated with decreased serum copper concentrations include malnutrition,
hypoproteinemia, malabsorption, nephrotic syndrome, Menkes disease, copper toxicity, and megadosing
of zinc-containing vitamins (zinc interferes with normal copper absorption from the gastrointestinal tract).
Hypercupremia is found in primary biliary cirrhosis, primary sclerosing cholangitis, hemochromatosis,
malignant diseases (including leukemia), thyrotoxicosis, and various infections. Serum copper
concentrations are also elevated in patients taking contraceptives or estrogens and during pregnancy.
Since the gastrointestinal (GI) tract effectively excludes excess copper, it is the GI tract that is most
affected by copper ingestion. Increased serum concentration does not, by itself, indicate copper toxicity.
Useful For: Diagnosis of: -Wilson disease -Primary biliary cirrhosis -Primary sclerosing cholangitis
Interpretation: Serum copper below the normal range is associated with Wilson disease, as well as a
variety of other clinical situations (see Clinical Information). Excess use of denture cream containing zinc
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