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Epic Code LAB848 Zinc, 24 Hour, Urine

Important Note

Order as Reference Miscellaneous #LAB848; indicate complete test name when ordering.

Additional Codes

Mayo Code: ZNU

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Useful For

Identifying the cause of abnormal serum zinc concentrations using a 24-hour urine specimen

Specimen Type

Urine
Laboratory Test Directory Note:

Refrigeration during and after urine collection is the preferred means of urine preservation.


Ordering Guidance


The use of blood testing is recommended for children younger than 10 years of age. Order ZN_S / Zinc, Serum.



Necessary Information


24-Hour volume (in milliliters) is required.



Specimen Required


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

Supplies: Urine Tubes, 10 mL (T068)

Collection Container/Tube: Clean, plastic urine collection container with no metal cap or glued insert

Submission Container/Tube: Plastic urine tube or clean, plastic aliquot container with no metal cap or glued insert

Specimen Volume: 10 mL

Collection Instructions:

1. Collect urine for 24 hours.

2. Refrigerate specimen within 4 hours of completion of 24-hour collection.

3. See Metals Analysis Specimen Collection and Transport for complete instructions.

Additional Information: See Urine Preservatives-Collection and Transportation for 24-Hour Urine Specimens for multiple collections.


Specimen Minimum Volume

0.4 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Urine Refrigerated (preferred) 28 days
  Ambient  28 days
  Frozen  28 days

Urine Preservative Collection Options

Note: The addition of preservative or application of temperature controls must occur within 4 hours of completion of the collection.

Ambient (no additive)

OK

Refrigerate (no additive)

Preferred

Frozen (no additive)

OK

50% Acetic Acid

OK

Boric Acid

No

Diazolidinyl Urea

No

6M Hydrochloric Acid

OK

6M Nitric Acid

OK

Sodium Carbonate

No

Thymol

No

Toluene

No

Reject Due To

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

Day(s) Performed

Monday, Thursday

Reference Values

0-17 years: Not established

≥18 years: 109-1,476 mcg/24 hours

Clinical Information

Zinc is an essential element; it is a critical cofactor for carbonic anhydrase, alkaline phosphatase, RNA and DNA polymerases, alcohol dehydrogenase, and many other physiologically important proteins. Zinc is a key element required for active wound healing.

 

Zinc depletion occurs because it is either not absorbed from the diet (excess copper or iron interfere with absorption) or lost after absorption. Dietary deficiency may be due to absence (parenteral nutrition), or because the zinc in the diet is bound to fiber and not available for absorption. Once absorbed, the most common route of loss is via exudates from open wounds, such as third-degree burns, or gastrointestinal loss as in colitis. Hepatic cirrhosis also causes excess loss of zinc by enhancing renal excretion. The peptidase, kinase, and phosphorylase enzymes are most sensitive to zinc depletion.

 

Zinc excess is not of major clinical concern. The popular American habit of taking megavitamins (containing huge doses of zinc) produces no direct toxicity problems. Much of this zinc passes through the gastrointestinal tract and is excreted in the feces. The excess fraction that is absorbed is excreted in the urine. The only known effect of excessive zinc ingestion relates to the fact that zinc interferes with copper absorption, which can lead to hypocupremia.

Cautions

No significant cautionary statements

Interpretation

Fecal excretion of zinc is the dominant route of elimination. Renal excretion is a minor, secondary elimination pathway. Normal daily excretion of zinc in the urine is in the range of 20 to 967 mcg/24 hours.

 

High urine zinc associated with low serum zinc may be caused by hepatic cirrhosis, neoplastic disease, or increased catabolism.

 

High urine zinc with normal or elevated serum zinc indicates a large dietary source, usually in the form of high-dose vitamins.

 

Low urine zinc with low serum zinc may be caused by dietary deficiency or loss through exudation common in burn patients and those with gastrointestinal losses.

Reporting Name

Zinc, 24 Hr, U

Method Name

Inductively Coupled Plasma Mass Spectrometry (ICP-MS)

Method Description

The metal of interest is analyzed by inductively coupled plasma mass spectrometry.(Unpublished Mayo method)

CPT Code Information

84630

LOINC Code Information

Test ID Test Order Name Order LOINC Value
ZNU Zinc, 24 Hr, U 5765-3

 

Result ID Test Result Name Result LOINC Value
8591 Zinc, 24 Hr, U 5765-3
TM8 Collection Duration 13362-9
VL5 Urine Volume 3167-4

Report Available

2 to 5 days

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

Clinical Reference

1. Sata F, Araki S, Murata K, Aono H. Behavior of heavy metals in human urine and blood following calcium disodium ethylenediamine tetraacetate injection: observations in heavy metal workers. J Toxicol Environ Health A. 1998;54(3):167-178

2. Afridi HI, Kazi TG, Kazi NG, et al. Evaluation of cadmium, lead, nickel and zinc status in biological samples of smokers and nonsmokers hypertensive patients. J Hum Hypertens. 2010;24(1):34-43

3. Zorbas YG, Kakuris KK, Neofitov IA, Afoninos NI. Zinc utilization in zinc-supplemented and -unsupplemented healthy subjects during and after prolonged hypokinesia. Tr Elem Electro. 2008;25(2):60-68

4. Rifai N, Horwath AR, Wittwer CT, eds. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 6th ed. Elsevier; 2018