Screening for occupational exposure
Monitoring metallic prosthetic implant wear
Dynamic Reaction Cell-Inductively Coupled Plasma-Mass Spectometry (DRC-ICP-MS)
Chromium (Cr)
Cr (Chromium)
Serum
The FDA-recommended test for monitoring chromium in patients with metal-on-metal implants is CRWB / Chromium, Blood.
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 96 hours.
Supplies: Metal Free Specimen Vial (T173)
Collection Container/Tube: Plain, royal blue-top Vacutainer plastic trace element blood collection tube
Submission Container/Tube: 7-mL Mayo metal-free, screw-capped, polypropylene vial
Specimen Volume: 1.6 mL
Collection Instructions:
1. Allow the specimen to clot for 30 minutes; then centrifuge the specimen to separate serum from the cellular fraction.
2. Remove the stopper. Carefully pour specimen into a Mayo metal-free, polypropylene vial, avoiding transfer of the cellular components of blood. Do not insert a pipet into the serum to accomplish transfer, and do not ream the specimen with a wooden stick to assist with serum transfer.
3. See Trace Metals Analysis Specimen Collection and Transport for complete instructions.
0.4 mL
Gross hemolysis | OK |
Gross lipemia | OK |
Gross icterus | OK |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Serum | Refrigerated (preferred) | 28 days | METAL FREE |
Ambient | 28 days | METAL FREE | |
Frozen | 28 days | METAL FREE |
Screening for occupational exposure
Monitoring metallic prosthetic implant wear
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.
Serum Cr concentrations are likely to be increased above the
<0.3 ng/mL
When collected by a phlebotomist experienced in ultra-clean collection technique and handled according to the instructions in Trace Metals Analysis Specimen Collection and Transport in Special Instructions, we have observed the concentration of chromium in serum to be <0.3 ng/mL. However, the majority of specimens submitted for analysis from unexposed individuals contain 0.3 ng/mL to 0.9 ng/mL of chromium. Commercial evacuated blood collection tubes not designed for trace-metal specimen collection yield serum containing 2.0 ng/mL to 5.0 ng/mL chromium derived from the collection tube.
Results greater than the flagged value indicate clinically significant exposure to chromium (Cr) (see Cautions about specimen collection). The reported units of measurement for chromium of ng/mL is equivalent to mcg/L.
Prosthesis wear is known to result in an increased circulating concentration of metal ions. A modest increase (0.3-0.6 ng/mL) in serum Cr concentration is likely to be associated with a prosthetic device in good condition. Serum concentrations above 1 ng/mL in a patient with a Cr-based implant suggest significant prosthesis wear. Increased serum trace element concentrations in the absence of corroborating clinical information do not independently predict prosthesis wear or failure. However, the FDA recommends testing chromium in EDTA anticoagulated whole blood in symptomatic patients with metal-on-metal implants.
Specimens from unexposed individuals collected using metal-free collection procedures typically have chromium above 0.3 ng/mL. Chromium is present in our environment at 100-fold to 1,000-fold higher concentration than found in biological tissues. Reports of increased serum chromium could be due to external contamination. Metal-free serum collection procedures must be followed, and centrifuged serum must be aliquoted into a Mayo Clinic Laboratories metal-free vial to avoid external contamination. Specimens collected using an anticoagulant are unacceptable; trace amounts of chromium are present in anticoagulants used in evacuated collection tubes.
1. Vincent JB: Elucidating a biological role for chromium at a molecular level. Acc Chem Res 2000 July;33(7):503-510
2. NIOSH Hexavalent Chromium Criteria Document Update. September 2008; Available at www.cdc.gov/niosh/topics/hexchrom/
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
4. Tower SS: Arthroprosthetic cobaltism: Neurological and cardiac manifestations in two patients with metal-on-metal arthroplasty: A case report. J Bone Joint Surg Am 2010;92:1-5
Chromium (Cr) in serum is analyzed by inductively coupled plasma-mass spectometry (ICP-MS) in dynamic reaction cell (DRC) mode using rhodium (Rh) as an internal standard and a salt matrix calibration.(Unpublished Mayo method)
Tuesday, Wednesday, Friday
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.
82495
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
CRS | Chromium, S | 5622-6 |
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.
|
---|---|---|
8638 | Chromium, S | 5622-6 |