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Test Code CRCRU Chromium/Creatinine Ratio, Random, Urine


Ordering Guidance


High concentrations of gadolinium and iodine are known to interfere with most metal tests. If either gadolinium- or iodine-containing contrast media has been administered, a specimen should not be collected for 96 hours.



Specimen Required


Supplies: Urine Tubes, 10 mL (T068)

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

Submission Container/Tube: Plastic vial 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

Detecting chromium exposure

Profile Information

Test ID Reporting Name Available Separately Always Performed
CRCRR Chromium/Creat Ratio, U No Yes
CRETR Creatinine, Random, U No Yes

Method Name

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

CRETR: Enzymatic Colorimetric Assay

Reporting Name

Chromium/Creat Ratio, Random, U

Specimen Type

Urine

Specimen 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

Chromium (Cr) has an atomic mass of 51.996, atomic number 24, and valences ranging from 2to 6(+). Hexavalent chromium, Cr(6+), and trivalent chromium, Cr(3+), are the 2 most prevalent forms. Cr(3+) is the only oxidation state present under normal physiologic conditions. Cr(6+) is widely used in industry to make chromium alloys including stainless steel pigments and electroplated coatings. Cr(6+), a known carcinogen, is rapidly metabolized to Cr(3+). Cr(3+) is the only form present in human urine.

Reference Values

0-17 years: Not established

>17 years: <0.8 mcg/g Creatinine

Interpretation

Chromium is principally excreted in the urine. Results greater than the reference range indicate either recent exposure to chromium or specimen contamination during collection.

 

The National Institute for Occupational Safety and Health document on occupational exposure reviews the data supporting use of urine to assess chromium exposure. The biological exposure index (BEI) for total chromium in urine measured at the end of the shift at the end of the workweek is 25 mcg/L. The BEI for the increase in total chromium during a shift is 10 mcg/L. A test for this specific purpose (CRUO / Chromium Occupational Exposure, Random, Urine) is available.

Specimen Retention Time

14 days

Performing 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

82495

82570

LOINC Code Information

Test ID Test Order Name Order LOINC Value
CRCRU Chromium/Creat Ratio, Random, U 13464-3

 

Result ID Test Result Name Result LOINC Value
CRETR Creatinine, Random, U 2161-8
607759 Chromium/Creat Ratio, U 13464-3

Day(s) Performed

Tuesday, Wednesday, Friday

Report Available

1 to 4 days