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Test Code ALWB Aluminum, Blood


Specimen Required


Patient Preparation: High concentrations of gadolinium and iodine are known to potentially interfere with most inductively coupled plasma mass spectrometry-based metal tests. If either gadolinium- or iodine-containing contrast media has been administered, a specimen should not be collected for 96 hours.

Supplies:

-Greiner Bio-One VACUETTE TUBE 6 mL NH Trace Elements Sodium Heparin tube (T819)

-Metal Free Specimen Vial (T173)

Container/Tube: Greiner Bio-One VACUETTE TUBE 6 mL NH Trace Elements Sodium Heparin tube

Specimen Volume: 1 mL

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


Secondary ID

622056

Useful For

Preferred test for routine aluminum screening

 

Monitoring metallic prosthetic implant wear

Method Name

Triple-Quadrupole Inductively Coupled Plasma Mass Spectrometry (ICP-MS/MS)

Reporting Name

Aluminum, B

Specimen Type

Whole blood

Specimen Minimum Volume

0.4 mL

Specimen Stability Information

Specimen Type Temperature Time
Whole blood Refrigerated 14 days

Reject Due To

Gross hemolysis OK
Gross lipemia OK
Gross icterus OK

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 at risk 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.

 

Blood 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 the prosthesis product information of each device for composition details.

Reference Values

0-17 years: Not established

≥18 years: <5 ng/mL

Interpretation

Internal exposure, which can be determined from aluminum levels in blood, is a significantly better measure for assessing aluminum-related neurotoxicity. Early signs of neurotoxicity have been reported in plasma concentrations starting at 13 ng/mL, but any elevation must take into account the full clinical history and other clinical signs and symptoms and test results. Previous studies have reported a whole blood to serum ratio for aluminum of approximately 1.7.(1)

 

The McCarthy(2) and Hernandez(3) 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.(4) A 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.

CPT Code Information

82108

LOINC Code Information

Test ID Test Order Name Order LOINC Value
ALWB Aluminum, B 5575-6

 

Result ID Test Result Name Result LOINC Value
622056 Aluminum, B 5575-6