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Test Code ALUCR Aluminum/Creatinine Ratio, Random, Urine


Ordering Guidance


The recommended test for routine aluminum screening is AL / Aluminum, Serum

 

For monitoring aluminum exposure or metallic prosthetic implant wear, the preferred test is ALU / Aluminum, 24 Hour, Urine.



Specimen Required


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: Urine Tubes, 10 mL (T068)

Collection Container/Tube: Clean, plastic urine collection container

Submission Container/Tube: Plastic urine tube or clean, plastic aliquot container with no metal cap or glued insert

Specimen Volume: 3 mL

Collection Instructions:

1. Collect a random urine specimen.

2. See Metals Analysis Specimen Collection and Transport for complete instructions.


Secondary ID

610838

Useful For

Monitoring aluminum exposure when a 24-hour urine cannot be collected

 

Monitoring metallic prosthetic implant wear when a 24-hour urine cannot be collected

 

This test is not an acceptable substitute for serum aluminum measurements and is not recommended for routine aluminum screening.

Profile Information

Test ID Reporting Name Available Separately Always Performed
ALCU Aluminum/Creat Ratio, U No Yes
CRETR Creatinine, Random, U No Yes

Method Name

ALCU: Inductively Coupled Plasma Mass Spectrometry (ICP-MS)

CRETR: Enzymatic Colorimetric Assay

Reporting Name

Aluminum/Creat Ratio, Random, U

Specimen Type

Urine

Specimen Minimum Volume

0.7 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Urine Refrigerated (preferred) 28 days
  Frozen  28 days
  Ambient  14 days

Reject Due To

  All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

Clinical Information

Under normal physiologic conditions, the usual daily dietary intake of aluminum (5-10 mg) is eliminated completely. Excretion is accomplished by avid filtration of aluminum from the blood by the glomeruli of the kidney. Patients in kidney failure lose the ability to clear aluminum and are candidates for aluminum toxicity.

 

Many factors increase the incidence of aluminum toxicity in patients with kidney failure:

-Aluminum-laden dialysis water can expose dialysis patients to aluminum.

-Aluminum-laden albumin can expose patients to an aluminum burden they cannot eliminate.

-The dialysis process is not highly effective at eliminating aluminum.

-Aluminum-based phosphate binder gels are administered orally to minimize phosphate accumulation; a small fraction of this aluminum may be absorbed and accumulated.

 

If it is not removed by kidney filtration, aluminum accumulates in the blood where it binds to proteins such as albumin and is rapidly distributed through the body. Aluminum overload leads to accumulation of aluminum at two sites: brain and bone. Brain deposition has been implicated as a cause of dialysis dementia. In bone, aluminum replaces calcium at the mineralization front, disrupting normal osteoid formation.

 

Urine aluminum concentrations are likely to be increased above the reference range in patients with metallic joint prosthesis. Prosthetic devices produced by Zimmer Company and Johnson and Johnson typically are made of aluminum, vanadium, and titanium. This list of products is incomplete, and these products change occasionally; see prosthesis product information for each device for composition details.

Reference Values

ALUMINUM:

0-17 years: Not established

≥18 years: <14 mcg/g creatinine

 

CREATININE:

16-326 mg/dL

Reference values have not been established for patients younger than 18 years of age.

Interpretation

Daily excretion more than 10 mcg/24 hours indicates exposure to aluminum. Prosthesis wear is known to result in increased circulating concentration of metal ions.(1) Modest increase (10-20 mcg/24 hours) in urine aluminum concentration is likely to be associated with a prosthetic device in good condition. Urine concentrations more than 50 mcg/24 hours in a patient with an aluminum-based implant, not undergoing dialysis, suggest significant prosthesis wear. Increased urine trace element concentrations in the absence of corroborating clinical information do not independently predict prosthesis wear or failure.

 

In kidney failure, the ability of the kidney to excrete aluminum decreases, while the exposure to aluminum increases (aluminum-laden dialysis water, aluminum-laden albumin, and aluminum-laden phosphate binders).

 

Patients receiving chelation therapy with desferrioxamine (for iron- or aluminum-overload states) also excrete considerably more aluminum in their urine than normal.

Day(s) Performed

Tuesday

Report Available

2 to 8 days

Specimen Retention Time

14 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

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

CPT Code Information

82570

82108

LOINC Code Information

Test ID Test Order Name Order LOINC Value
ALUCR Aluminum/Creat Ratio, Random, U 13470-0

 

Result ID Test Result Name Result LOINC Value
CRETR Creatinine, Random, U 2161-8
610839 Aluminum/Creat Ratio, U 13470-0