Sorted By Test Name - Mayo Medical Laboratories

CUU
8590
CUT
8687
2000;124:71-81 2. Homburger HA: Cascade testing for autoantibodies in connective tissue diseases.
Mayo Clin Proc 1995;70:183-184 3. van Boekel MA, Vossenaar ER, van den Hoogen FH, van Venrooij
WJ: Autoantibody systems in rheumatoid arthritis: specificity, sensitivity and diagnostic value. Arthritis
Res 2002;4:87-93 4. Tomar R, Homburger H: Assessment of immunoglobulins and antibodies. In Clinical
Immunology Principles and Practice, 2nd edition. Edited by R Rich, T Fleisher, W Shearer, et al, St.
Louis, Mosby-Year Book, 2001, pp 120.1-120.14
Copper, 24 Hour, Urine
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/day 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/specimen
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
July;118(1):16-20
Copper, Liver Tissue
Clinical Information: Homeostatic regulation of copper metabolism is very complex. The liver is the
key organ to facilitate copper storage and incorporation of copper into the transport protein ceruloplasmin.
Intestinal absorption and biliary excretion also play major roles in the regulation of copper homeostasis.
Abnormal copper metabolism is associated with liver disease. Elevated serum copper concentrations are
seen in portal cirrhosis, biliary tract disease, and hepatitis, probably because excess copper that would
normally be excreted in the bile is retained in circulation. In primary biliary cirrhosis, ceruloplasmin is
high, resulting in high serum copper. Lesser elevations of hepatic copper are found in chronic copper
poisoning, obstructive jaundice, and certain cases of hepatic cirrhosis. Reduced serum copper
concentration is typical of Wilson disease (hepatolenticular degeneration). Wilson disease is characterized
by liver disease, neurologic abnormalities, and psychiatric disturbances. Kayser-Fleischer rings are
normally present and urinary copper excretion is increased, while serum copper and ceruloplasmin are
low.
Useful For: Diagnosing Wilson disease and primary biliary cirrhosis
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