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Test Catalog

Test ID: CRCOF    
Chromium and Cobalt, Synovial Fluid

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

Monitoring metallic prosthetic implant wear and local tissue destruction in failed hip arthroplasty constructs

 

This test is not useful for assessment of vitamin B12 activity.

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

Per FDA recommendations, orthopedic surgeons should consider measuring and following serial chromium (Cr) and cobalt (Co) concentrations in EDTA anticoagulated whole blood in symptomatic patients with metal-on-metal hip implants as part of their overall clinical evaluation. However, a recent publication(1) has shown synovial fluid measurements were superior to whole blood and serum Cr and Co concentrations in predicting local tissue destruction in failed hip arthroplasty constructs.

 

Prosthetic devices produced by Depuy Company, Dow Corning, Howmedica, LCS, PCA, Osteonics, Richards Company, Tricon, and Whiteside are typically made of Cr, Co, and molybdenum. This list of products is incomplete, and the products' compositions change occasionally; see each prostheses' product information for composition details.

 

Cr:

Cr is a naturally-occurring element widely distributed in the environment. It exists in several valence states with the 3 main forms being Cr(0), Cr(III), and Cr(VI). Cr(III) is an essential trace element that enhances the action of insulin. Deficiency leads to impaired growth, reduced life span, corneal lesions, and alterations in carbohydrates, lipid, and protein metabolism.

 

Cr is widely used in manufacturing processes to make various metal alloys such as stainless steel. It is also used in many consumer products including: wood treated with copper dichromate, leather tanned with chromic sulfate, and metal-on-metal hip replacements.

 

The general population is most likely to be exposed to trace levels of Cr, as Cr(III) is naturally occurring in foods, such as fruits, vegetables, nuts, beverages, and meats. The highest potential occupational exposure occurs in the metallurgy and tanning industries, where workers may be exposed to high air concentrations.

 

Co:

Co is a naturally occurring, hard, grey element widely distributed in the environment. It is used to produce alloys in the manufacturing of aircraft engines, cutting tools, and some artificial hip and knee joint prosthesis devices. 

 

Co is an essential cofactor in vitamin B12, which is necessary for neurological function, brain function, and the formation of blood. For most people, food is the largest source of Co intake. However, more than a million workers are potentially exposed to Co and its compounds, with the greatest exposure in mining processes, cemented tungsten-carbide industry, Co powder industry, and alloy production industry.

 

Co is not highly toxic, but large doses will produce adverse clinical manifestations. Acute symptoms include pulmonary edema, allergy, nausea, vomiting, hemorrhage, and renal failure. Chronic exposure to Co-containing hard metal (dust or fume) can result in a serious lung disease called "hard metal lung disease," which is a type of pneumoconiosis (lung fibrosis). Furthermore, inhalation of Co particles can cause respiratory sensitization, asthma, shortness of breath, and decreased pulmonary function. Even though the primary route of occupational exposure to Co is the respiratory tract, skin contact is also important because dermal exposures to hard metal and cobalt salts can result in significant systemic uptake. Sustained exposures can cause skin sensitization, which may result in eruptions of contact dermatitis. In cases of suspected toxicity, blood, serum, or urine concentrations of Co can be checked. Vitamin B12 should be used to assess nutritional status.

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.

CHROMIUM:

0-17 years: Not established

> or =18 years: <17.1 ng/mL

 

COBALT:

0-17 years: Not established

> or =18 years: <17.2 ng/mL

Interpretation Provides information to assist in interpretation of the test results

Chromium:

Based on an internal study, synovial fluid chromium concentrations of 17.1 ng/mL or above were more likely due to a metal reaction (eg adverse local tissue reaction [ALTR]/adverse reaction to metal debris [ARMD]) versus a nonmetal reaction in patients undergoing metal-on-metal revision (sensitivity of 84.6% and specificity of 85.2%).

 

Cobalt:

Based on an internal study, synovial fluid cobalt concentrations of 17.2 ng/mL or above were more likely due to a metal reaction (eg, adverse local tissue reaction [ALTR]/adverse reaction to metal debris [ARMD]) versus a nonmetal reaction in patients undergoing metal-on-metal revision (sensitivity of 80.8% and specificity of 81.5%).

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

Chromium:

Chromium is present in our environment at 100-fold to 1000-fold higher concentration than found in biological tissues. Reports of increased chromium could be due to external contamination. Metal-free blood collection procedures must be followed. Elevated trace element concentrations in the absence of corroborating clinical information do not independently predict prosthesis wear or failure.

 

Cobalt:

Because this test uses mass spectrometry detection, the radioactive form of cobalt, (60)Co, is not quantified.

 

Specimen collection procedures for cobalt require special specimen collection tubes, rigorous attention to ultraclean specimen collection and handling procedures, and analysis in an ultraclean facility. Elevated trace element concentrations in the absence of corroborating clinical information do not independently predict prosthesis wear or failure.

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

1. Houdek MT, Wyles CC, Jannetto PJ, et al: Synovial fluid metal levels are superior to whole blood and serum metal ion levels in predicting local tissue destruction in failed hip arthroplasty constructs. Orthopaedic Proceed. 2018;100-B(SUPP_1):39

2. Eltit F, Assiri A, Garbuz D, et al: Adverse reactions to metal on polyethylene implants: Highly destructive lesions related to elevated concentration of cobalt and chromium in synovial fluid. J Biomed Mater Res A. 2017;105(7):1876-1886

3. Lass R, Grubl A, Kolb A, et al: Comparison of synovial fluid, urine, and serum ion levels in metal-on-metal total hip arthroplasty at minimum follow-up of 18 years. J Orthop Res. 2014;32(9):1234-1240

4. De Pasquale D, Stea S, Squarzoni S, et al: Metal-on-metal hip prostheses: Correlation between debris in the synovial fluid and levels of cobalt and chromium ions in the bloodstream. Int Orthop. 2014;38(3):469-475

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