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HelpMayo Test ID ZNUCR Zinc/Creatinine Ratio, Random, Urine
Ordering Guidance
The use of blood testing is recommended for children younger than 10 years. Order ZN_S / Zinc, Serum.
Specimen Required
Patient Preparation: High concentrations of barium are known to interfere with most metal tests. 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: 3 mL
Collection Instructions:
1. Collect a random urine specimen.
2. See Metals Analysis Specimen Collection and Transport for complete instructions.
Useful For
Identifying the cause of abnormal serum zinc concentrations using a random urine specimen
Profile Information
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| ZNCU | Zinc/Creat Ratio, U | No | Yes |
| CRETR | Creatinine, Random, U | No | Yes |
Special Instructions
Method Name
ZNCU: Triple-Quadrupole Inductively-Coupled Plasma Mass Spectrometry (ICP-MS/MS)
CRETR: Enzymatic Colorimetric Assay
Reporting Name
Zinc/Creat Ratio, Random, USpecimen Type
UrineSpecimen Minimum Volume
2 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Urine | Refrigerated (preferred) | 28 days | |
| Frozen | 28 days | ||
| Ambient | 14 days |
Reject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.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.
Reference Values
ZINC/CREATININE:
0-17 years: Not established
≥18 years: 89-910 mcg/g creatinine
CREATITINE:
≥18 years old: 16-326 mg/dL
Reference values have not been established for patients who are younger than 18 years.
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 89 to 910 mcg/g creatinine.
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.
Cautions
No significant cautionary statements
Clinical Reference
1. Sata F, Araki S, Murata K, Aono H. Behaviour 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. Roohani N, Hurrell R, Kelishadi R, Schulin R. Zinc and its importance for human health: An integrative review. J Res Med Sci. 2013;18(2):144-157
5. Rifai N, Horwath AR, Wittwer CT, eds. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 6th ed. Elsevier; 2018
Method Description
The metal of interest is analyzed by triple-quadrupole inductively-coupled plasma mass spectrometry.(Unpublished Mayo method)
Day(s) Performed
Monday, Thursday
Report Available
2 to 5 daysSpecimen Retention Time
14 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
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.CPT Code Information
84630
82570
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| ZNUCR | Zinc/Creat Ratio, Random, U | 13473-4 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 615260 | Zinc/Creat Ratio, U | 13473-4 |
| CRETR | Creatinine, Random, U | 2161-8 |