Copper, Urine (Sendout)

Copper: Dynamic Reaction Cell-Inductively Coupled Plasma-Mass Spectrometry (DRC-ICP-MS)

Creatinine (only performed for random specimens): Enzymatic

Reference range applies to 24-hour urine collections only.

Reference values have not been established for patients who are less than 18 years of age.

Interpretation:

Humans normally excrete less than 60 mcg/day of copper in the urine.

Urinary copper excretion greater than 60 mcg/day may be seen in:

• Wilson 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.

Patient Preparation: High concentrations of barium are known to interfere with this test. If barium-containing contrast media has been administered, a specimen should not be collected for at least 96 hours.

Collection:

• 24-Hour Urine:
  • Collect urine for 24 hours in a preservative-free amber polyethylene 24-hr urine collection container (with no metal caps or glued inserts).
  • Refer to Mayo Urine Preservatives-Collection and Transportation for 24-Hour Urine Specimens for additional information on acceptable collection conditions.
  • Refrigerate urine within 4 hours of completion of collection.
  • The collection interval must be between 22 and 26 hours. Samples with collection intervals <22 hours and >26 hours will be rejected by Mayo for the 24-hour test, but can be processed for the random test with approval from the provider.
• Random Urine: Collect random urine in a sterile screw-cap container (with no metal cap or glued insert).

Outside Laboratories:

• 24-Hour Collection:
  • Mix specimen well. Measure and record total volume. Note the collection interval and total volume on the requisition.
  • Aliquot urine into a Mayo metal-free screw-capped vial (T173)* and refrigerate.
  • The collection interval must be between 22 and 26 hours. Samples with collection intervals <22 hours and >26 hours will be rejected by Mayo for the 24-hour test, but can be processed for the random test.
• Random Urine: Aliquot urine into a Mayo metal-free screw-capped vial (T173)* and refrigerate.

*Note: Mayo T173 is recommended, but not required.

Stability:

• 24-Hour Urine: Refrigerated (Preferred): 28 days; Frozen: 28 days; Ambient: 28 days.
• Random Urine: Refrigerated (Preferred): 28 days; Frozen: 28 days; Ambient: 14 days.

All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

SPS: Specimen must be refrigerated within 4 hours of completion of 24-hour collection.

• 24-Hour Collection: Mix specimen well. Measure and record total volume. Aliquot urine into a Mayo metal-free screw-capped vial (T173)* and refrigerate.
  • The collection interval must be between 22 and 26 hours.
• Random Urine: Aliquot urine into a Mayo metal-free screw-capped vial (T173)* and refrigerate.

*Note: Mayo T173 is recommended, but not required.

Sendouts:

• 24-Hour Urine: Order Mayo Test: CUU.
• Random: Batch order over the interface. In MayoAccess, add test CURCU (Copper/Creatinine Ratio) and remove test CUU.
• Interfaced: Yes.

Stability:

• 24-Hour Urine: Refrigerated (Preferred): 28 days; Frozen: 28 days; Ambient: 28 days.
• Random Urine: Refrigerated (Preferred): 28 days; Frozen: 28 days; Ambient: 14 days.