Chromium/Creatinine Ratio, Random, Urine
Use
This test is useful for detecting exposure to chromium by measuring the chromium to creatinine ratio in a random urine specimen. Elevated results suggest recent exposure to chromium or possible specimen contamination. Reference intervals are provided for individuals over age 17 (less than 0.8 mcg/g creatinine), while values for ages 0–17 years are not established. The test provides insight into chromium excretion, with heightened care required to avoid contamination during specimen collection and handling.
Special Instructions
Patient preparation includes avoiding specimen collection for 96 hours after administration of gadolinium‑ or iodine‑containing contrast media due to potential interference. Required supplies include 10 mL urine tubes (T068). Collection must use a clean plastic urine container without metal caps or glued inserts. Submission should use a plastic vial or clean plastic aliquot container similarly metal‑free.
Limitations
Normal urine chromium levels are extremely low, and elevated results may result from external contamination rather than true exposure. The test requires ultraclean specimen collection procedures, specialized tubes, and handling in ultraclean facilities. High concentrations of gadolinium or iodine contrast agents can interfere with testing, and refrigeration is preferred over chemical preservation. Specimens not meeting these criteria may yield misleading results.
New York Approved
Methodology
Mass Spectrometry (ICP‑MS/MS)
Biomarkers
LOINC Codes
- 13464-3
- 2161-8
- 13464-3
Result Turnaround Time
1-4 days
Related Documents
For more information, please review the documents below
Specimen
Urine
Volume
3 mL
Minimum Volume
2 mL
Container
Clean plastic urine container with no metal cap or glued insert; submission in plastic vial or clean plastic aliquot container with no metal cap or glued insert
Collection Instructions
Collect a random urine specimen; see Metals Analysis Specimen Collection and Transport for complete instructions
Patient Preparation
Do not collect specimen for 96 hours after gadolinium‑ or iodine‑containing contrast media
Causes for Rejection
Specimens not suitable; all specimens will be evaluated for test suitability
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 14 days |
| Refrigerated | 28 days |
| Frozen | 28 days |