Test Catalog

Test ID: CRU    
Chromium, 24 Hour, Urine

Useful For Suggests clinical disorders or settings where the test may be helpful

Screening for occupational exposure to chromium


Monitoring metallic prosthetic implant wear

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Chromium (Cr) exists in valence states ranging from 2(-) to 6(+). Hexavalent chromium (Cr[6+]) and trivalent chromium (Cr[3+]) are the 2 most prevalent forms. Cr(6+) is used in industry to make chromium alloys including stainless steel, pigments, and electroplated coatings. Cr(6+), a known carcinogen, is immediately converted to Cr(3+) upon exposure to biological tissues. Cr(3+) is the only chromium species found in biological specimens.


Urine chromium concentrations are likely to be increased above the reference range in patients with metallic joint prosthesis. Prosthetic devices produced by Depuy Company, Dow Corning, Howmedica, LCS, PCA, Osteonics, Richards Company, Tricon, and Whiteside typically are made of chromium, cobalt, and molybdenum. This list of products is incomplete, and these products change occasionally; see prosthesis product information for each device for composition details.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

0-17 years: not established

> or =18 years: 0.1-1.2 mcg/24 hours

Interpretation Provides information to assist in interpretation of the test results

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


Prosthesis wear is known to result in increased circulating concentration of metal ions. Modest increase (8-16 mcg/24 hour) in urine chromium concentration is likely to be associated with a prosthetic device in good condition. Urine concentrations greater than 20 mcg/24 hours in a patient with chromium-based implant suggest significant prosthesis wear. Increased urine trace element concentrations in the absence of corroborating clinical information do not independently predict prosthesis wear or failure.


The National Institute for Occupational Safety and Health (NIOSH) draft document on occupational exposure reviews the data supporting use of urine to assess chromium exposure. They recommend a Biological Exposure Index of 10 mcg/g creatinine and 30 mcg/g creatinine for the increase in urinary chromium concentrations during a work shift and at the end of shift at the end of the workweek, respectively. A test for this specific purpose (CROMU / Chromium for Occupational Monitoring, Random, Urine) is available.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Vincent JB: Elucidating a biological role for chromium at a molecular level. Acc Chem Res. 2000 July;33(7):503-510

2. The National Institute for Occupational Safety and Health (NIOSH): NIOSH Criteria Document: Criteria for a Recommendation Standard for an Occupational Exposure to Hexavalent Chromium. September 2013 Available at www.cdc.gov/niosh/docs/2013-128/pdfs/2013_128.pdf

3. Keegan GM, Learmonth ID, Case CP: A systematic comparison of the actual, potential, and theoretical health effects of cobalt and chromium exposures from industry and surgical implants. Crit Rev Toxicol. 2008;38:645-674

Special Instructions Library of PDFs including pertinent information and forms related to the test