Sign in →

Test Code ZNCRU Zinc/Creatinine Ratio, Random, Urine

Reporting Name

Zinc/Creat Ratio, Random, U

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
ZNCR Zinc/Creat Ratio, U No Yes
CDCR Creatinine Conc No Yes

Performing Laboratory

Mayo Medical Laboratories in Rochester

Specimen Type


Specimen Required

Patient Preparation:

High concentrations of barium are known to interfere with most metals tests. If barium-containing contrast media has been administered, a specimen should not be collected for 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 (T068) 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 Trace Metals Analysis Specimen Collection and Transport in Special Instructions for complete instructions.

Specimen Minimum Volume

0.7 mL

Specimen Stability Information

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

Reference Values

0-17 years: not established

≥18 years: 89-910 mcg/g Creatinine

Day(s) and Time(s) Performed

Tuesday, Thursday; 8 a.m.

Test Classification

See Individual Test IDs

CPT Code Information

84630 Zinc Concentration

82570 Creatinine Concentration

LOINC Code Information

Test ID Test Order Name Order LOINC Value
ZNCRU Zinc/Creat Ratio, Random, U In Process


Result ID Test Result Name Result LOINC Value
CDCR Creatinine Conc 2161-8
32876 Zinc/Creat Ratio, U 13473-4

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 also is a key element required for active wound healing.


Zinc depletion occurs either because it is not absorbed from the diet or it is 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 mega-vitamins (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.

Analytic Time

1 day

NY State Approved


Method Name

ZNCR: Inductively Coupled Plasma-Mass Spectrometry (ICP-MS)

CDCR: Enzymatic Colorimetric Assay