Chromium, Serum (CRS)

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Test Code: CHROSO

Overview
Ordering
Specimen
Performing
Clinical/Interpretive
Contacts
Coding

Synonyms/Keywords

Chromium (Cr), Cr (Chromium)

Useful For

Screening for occupational exposure

Monitoring metallic prosthetic implant wear

Specimen Requirements

Specimen Type	Preferred Container/Tube	Acceptable Container/Tube	Specimen Volume	Specimen Minimum Volume (allows for 1 repeat)	Pediatric Minimum Volume (no repeat)
Serum	Royal Blue Top Tube (RBTT) Metal Free, No Additive, 6 mL		1.6 mL

Collection Processing Instructions

1. Allow the specimen to clot for at least 30 minutes, but no longer than 4 hours. Centrifuge the specimen to separate serum from the cellular fraction.

2. Remove the stopper. Carefully pour serum specimen into a metal-free, screw-capped, polypropylene vial, avoiding transfer of the cellular components of blood.

DO NOT insert a pipet into the serum to accomplish transfer.

DO NOT ream the specimen with a wooden stick to assist with serum transfer.

Blood from a dialysis patient on heparin may produce an uncoagulated serum that forms a fibrin clot after centrifugation. Pour off serum as soon as possible, and repeat centrifugation step if more serum is needed.

3. See Metals Analysis-Collection and Transport in Special Instructions on Mayo website for complete instructions (Metals Analysis Specimen Collection and Transport)

Additional Information: High concentrations of gadolinium and iodine are known to interfere with most metals tests. If either gadolinium- or iodine-containing contrast media has been administered, a specimen should not be collected for 96 hours.

Specimen Stability Information

Specimen Type	Temperature	Time
Serum	Refrigerated (preferred)	28 days
	Ambient	28 days
	Frozen	28 days

Interference

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.

Performing Laboratory Information

Performing Location	Day(s) Test Performed	Report Available	Methodology/Instrumentation
Mayo Clinic Laboratories	Monday-Friday	1 to 4 days	Triple-Quadrupole Inductively Coupled Plasma Mass Spectrometry (ICP-MS/MS)

Reference Lab

Mayo Clinic Laboratories

Test Information

Chromium (Cr) exists in valence states. 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 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 Range Information

<0.4 ng/mL

When collected by a phlebotomist experienced in ultra-clean collection technique and handled according to the instructions in Metals Analysis Specimen Collection and Transport, we have observed the concentration of chromium in serum to be below 0.4 ng/mL. However, the majority of specimens submitted for analysis from unexposed individuals contain 0.1 ng/mL to 0.3 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.

Interpretation

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.

Outreach CPTs

CPT	Modifier (if needed)	Quantity	Description	Comments
82495		1

Synonyms/Keywords

Chromium (Cr), Cr (Chromium)

Ordering Applications

Ordering Application	Description
Cerner	Chromium Serum (CRS)

If the ordering application you are looking for is not listed, contact your local laboratory for assistance.

Specimen Requirements

Specimen Type	Preferred Container/Tube	Acceptable Container/Tube	Specimen Volume	Specimen Minimum Volume (allows for 1 repeat)	Pediatric Minimum Volume (no repeat)
Serum	Royal Blue Top Tube (RBTT) Metal Free, No Additive, 6 mL		1.6 mL

Collection Processing