Test Catalog

Test Id : COSY

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 nutritional status or potential cobalt toxicity.

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

Method Name
A short description of the method used to perform the test

Inductively Coupled Plasma-Mass Spectrometry (ICP-MS)

NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.


Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

Cobalt, Synovial Fl

Lists additional common names for a test, as an aid in searching

Cobalt (Co)

Co (Cobalt)

Specimen Type
Describes the specimen type validated for testing

Synovial Fluid

Ordering Guidance

This test should only be used in individuals with metallic prosthetic implants. The significance of cobalt concentrations in synovial fluid in patients without implants is unknown.

Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

Patient Preparation: 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 at least 96 hours

Container/Tube: Royal blue top (metal-free EDTA)

Specimen Volume: 1 mL

Collection Instructions: See Trace Metals Analysis Specimen Collection and Transport for complete instructions.

Additional Information: Cobalt is present in the black rubber plunger seals found in most disposable syringes. As a result, synovial fluid should not be collected in these devices as contamination may occur.

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

Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the Testing Laboratory

0.4 mL

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

Gross hemolysis OK
Gross lipemia OK
Gross icterus OK

Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

Specimen Type Temperature Time Special Container
Synovial Fluid Refrigerated (preferred) 90 days
Ambient 90 days
Frozen 90 days

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 nutritional status or potential cobalt toxicity.

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 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 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 chromium, Co, and molybdenum. This list of products is incomplete, and these products' compositions change occasionally; see each prostheses' product information for composition details.


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 for 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. The greatest environmental exposure occurs in mining processes, cemented tungsten-carbide industry, Co powder industry, and alloy production industry.


Co is not highly toxic; however large doses may 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.

0-17 years: Not established

> or =18 years: <19.8 ng/mL

Provides information to assist in interpretation of the test results

Based on an internal study, synovial fluid cobalt concentrations of 19.8 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 92.3% and specificity of 96.3%).

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

This test is intended for monitoring of implant wear and should not be ordered to assess nutritional status or potential cobalt toxicity.


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, Taunton MJ, Wyles CC, Jannetto PJ, Lewallen DG, Berry DJ: Synovial fluid metal ion levels are superior to blood metal ion levels in predicting an adverse local tissue reaction in failed total hip arthroplasty. J Arthroplasty. 2021 Sep;36(9):3312-3317.e1. doi: 10.1016/j.arth.2021.04.034

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 Jul;105(7):1876-1886. doi: 10.1002/jbm.a.36057

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 Sept;32(9):1234-1240. doi: 10.1002/jor.22652

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 Mar;38(3):469-475. doi: 10.1007/s00264-013-2137-5

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

Method Description
Describes how the test is performed and provides a method-specific reference

The metal of interest is analyzed by inductively coupled plasma mass spectrometry.(Unpublished Mayo method)

PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information


Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.


Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

2 to 8 days

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

14 days

Performing Laboratory Location
Indicates the location of the laboratory that performs the test


Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.

  • Authorized users can sign in to Test Prices for detailed fee information.
  • Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
  • Prospective clients should contact their Regional Manager. For assistance, contact Customer Service.

Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.

This test was developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.

CPT codes are provided by the performing laboratory.


LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.

Test Id Test Order Name Order LOINC Value
COSY Cobalt, Synovial Fl 23842-8
Result Id Test Result Name Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
606352 Cobalt, Synovial Fl 23842-8

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports

Test Update Resources

Change Type Effective Date
Test Changes - Reference Value 2022-04-14
Test Changes - Reference Value 2022-04-14