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HelpTest Code ALUM Aluminum, Serum
Additional Codes
| Mayo Test ID |
|---|
| AL |
Reporting Name
Aluminum, SUseful For
Preferred monitoring for aluminum toxicity in patients undergoing dialysis
Preferred test for routine aluminum screening
Monitoring metallic prosthetic implant wear
Method Name
Dynamic-Reaction Cell Inductively-Coupled Plasma Mass Spectrometry (DRC-ICP-MS)
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
SerumSpecimen 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:
-Metal Free B-D Tube (No Additive), 6 mL (T184)
-Metal Free Specimen Vial (T173)
Container/Tube: 6-mL Plain, royal blue-top Vacutainer plastic trace element blood collection tube
Submission Container/Tube: 7-mL Metal-free, screw-capped, polypropylene vial
Specimen Volume: 1.2 mL
Collection Instructions: See Metals Analysis Specimen Collection and Transport for complete instructions.
Specimen Minimum Volume
0.3 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum | Refrigerated (preferred) | 7 days | METAL FREE |
| Ambient | 7 days | METAL FREE | |
| Frozen | 7 days | METAL FREE |
Reject Due To
| Gross hemolysis | OK |
| Gross lipemia | OK |
| Gross icterus | OK |
Special Instructions
Reference Values
<7 ng/mL
<60 ng/mL (dialysis patients)
For International System of Units (SI) conversion for Reference Values, see www.mayocliniclabs.com/order-tests/si-unit-conversion.html
Day(s) Performed
Tuesday
CPT Code Information
82108
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| AL | Aluminum, S | 5574-9 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 8373 | Aluminum, S | 5574-9 |
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.
Deposition of aluminum in bone also interrupts normal calcium exchange. The calcium in bone becomes unavailable for resorption back into blood under the physiologic control of parathyroid hormone (PTH) and results in secondary hyperparathyroidism.
While PTH is typically quite elevated in kidney failure, two different processes may occur:
1) High-turnover bone disease associated with high PTH (>150 pg/mL) and relatively low aluminum (<20 ng/mL)
2) Low-turnover bone disease with lower PTH (<50 pg/mL) and high aluminum (>60 ng/mL). Low-turnover bone disease indicates aluminum intoxication.
Serum 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. 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.
Interpretation
Patients in kidney failure not receiving dialysis therapy invariably have serum aluminum levels above the 60 ng/mL range.
McCarthy(1) and Hernandez(2) describe a biochemical profile that is characteristic of aluminum overload disease in dialysis patients:
-Patients in kidney failure with no signs or symptoms of osteomalacia or encephalopathy usually had serum aluminum below 20 ng/mL and parathyroid hormone (PTH) concentrations above 150 pg/mL, which is typical of secondary hyperparathyroidism.
-Patients with signs and symptoms of osteomalacia or encephalopathy had serum aluminum above 60 ng/mL and PTH concentrations below 50 pg/mL (PTH above the reference range, but low for secondary hyperparathyroidism).
-Patients who had serum aluminum above 60 ng/mL but below 100 ng/mL were identified as candidates for later onset of aluminum-overload disease and required aggressive efforts to reduce their daily aluminum exposure. This was done by switching them from aluminum-containing phosphate binders to calcium-containing phosphate binders, by ensuring that their dialysis water had less than 10 ng/mL of aluminum, and ensuring the albumin used during postdialysis therapy was aluminum free.
Prosthesis wear is known to result in increased circulating concentration of metal ions.(3) Modest increase (6-10 ng/mL) in serum aluminum concentration is likely to be associated with a prosthetic device in good condition. Serum concentrations above 10 ng/mL in a patient with an aluminum-based implant not undergoing dialysis suggest significant prosthesis wear. Increased serum trace element concentrations in the absence of corroborating clinical information do not independently predict prosthesis wear or failure.
Cautions
Failure to pay attention to proper specimen collection procedures can cause abnormal results due to specimen contamination, which can lead to misinterpretation and misdiagnosis:
-Most of the common evacuated blood collection devices have rubber stoppers that are comprised of aluminum-silicate. Simple puncture of the rubber stopper for blood collection is sufficient to contaminate the specimen with aluminum. Typically, blood drawn in standard evacuated blood tubes will be contaminated by 20 to 60 ng/mL aluminum.
-The use of wooden applicator sticks or pipette tips during specimen aliquoting can cause abnormal results due to contamination.
-Royal Blue (BD) top tubes can potentially artificially elevate the aluminum value up to 15 ng/mL due to contamination. Interpret results with caution.
Method Description
The metal of interest is analyzed by inductively coupled plasma mass spectrometry.(Unpublished Mayo method)