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Test Code LABGDU Gadolinium, 24 Hour, Urine

Additional Codes

Test Name in EPIC EPIC Test Code Mnemonic Mayo Test ID
GADOLINIUM, 24 HOUR, URINE LABGDU GDU GDU

 

Reporting Name

Gadolinium, 24 Hr, U

Useful For

Assessing chronic exposure and monitoring effectiveness of dialysis in a 24-hour urine collection

Method Name

Inductively Coupled Plasma-Mass Spectrometry (ICP-MS)

Performing Laboratory

Mayo Medical Laboratories in Rochester

Specimen Type

Urine


Advisory Information


 



Necessary Information


24-Hour volume is required.



Specimen Required


Patient Preparation: 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.

Supplies: Urine Tubes, 10 mL (T068)

Container/Tube: Plastic, 10-mL urine tube (T068) or clean, plastic aliquot container with no metal cap or glued insert

Specimen Volume: 10 mL

Collection Instructions:

1. Collect urine for 24 hours.

2. Refrigerate specimen within 4 hours of completion of 24-hour collection.

3. See Trace Metals Analysis Specimen Collection and Transport in Special Instructions for complete instructions.

Additional Information: See Urine Preservatives-Collection and Transportation for 24-Hour Urine Specimens in Special Instructions for multiple collections.


Specimen Minimum Volume

0.4 mL

Specimen Stability Information

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

Reject Due To

Hemolysis

NA

Lipemia

NA

Icterus

NA

Other

NA

Reference Values

0-17 years: not established

≥18 years: <0.7 mcg/24 hour

Day(s) and Time(s) Performed

Thursday; 8 a.m.

CPT Code Information

83018

LOINC Code Information

Test ID Test Order Name Order LOINC Value
GDU Gadolinium, 24 Hr, U 8201-6

 

Result ID Test Result Name Result LOINC Value
29252 Gadolinium, 24 Hr, U 8201-6
TM101 Collection Duration 13362-9
VL82 Urine Volume 3167-4

Analytic Time

1 day

Cautions

Urine gadolinium concentration will be elevated if the specimen is collected less than 96 hours after administration of gadolinium-based contrast agents (GBCA). This elevation is due to the residual gadolinium present from contrast media infusion. An elevated gadolinium in a specimen collected more than 96 hours after contrast media infusion does not definitively indicate risk of nephrogenic systemic fibrosis (NSF) or gadolinium toxicity. Ultimately, patients should consult with their healthcare providers to interpret any test results.

 

Gadolinium may also be present in the effluent of metropolitan sewage treatment plants and in the rivers near metropolitan areas. Sewage treatment does not remove gadolinium. Anthropogenic sources of gadolinium could contribute to low concentrations of gadolinium excreted in the urine.

Supportive Data

An evaluation of urine gadolinium concentration in healthy human subjects not exposed to gadolinium within 96 hours of specimen collection generated a reference range of less than 0.7 mcg/24 hour (median value 0.2 mcg/24 hour) with no evidence of age or gender trend. Of unexposed patients, 95% had values below 0.1 mcg/24 hour.

Method Description

Gadolinium (Gd) in serum and urine is analyzed by inductively coupled plasma-mass spectrometry in standard mode using terbium (Tb) as an internal standard and a plasma matrix calibration.(Leung N, Pittelkow MR, Lee CU et al: Chelation of gadolinium with deferoxamine in a patient with nephrogenic systemic fibrosis. NDT Plus 2009;2[4]:309-311)

Interpretation

Elevated urine gadolinium results collected more than 96 hours after administration of a gadolinium-based contrast agent only confirms past exposure, or continued exposure through anthropogenic sources, and prolonged elimination of gadolinium. Gadolinium also has been shown to be present in some municipal water sources which may contribute to the observation of low concentrations of gadolinium in patients who never have been exposed to gadolinium-based contrast agents (GBCA).

 

Elevated gadolinium in a specimen collected more than 96 hours after contrast media infusion does not indicate risk of nephrogenic systemic fibrosis (NSF).

Specimen Retention Time

14 days

Clinical Information

Gadolinium is a member of the lanthanide series of the periodic table of elements and is considered a nonessential element. Due to its paramagnetic properties, chelated gadolinium is commonly employed as contrast media (gadolinium-based contrast agents: GBCA) for magnetic resonance imaging and computer tomography scanning.

 

Gadolinium is primarily eliminated via the kidneys, so exposure can be prolonged in patients with renal insufficiency. In healthy subjects with normal renal function, the plasma half-life of gadolinium is approximately 90 minutes (1.5 hours). Patients with reduced renal function and some patients with normal renal function may exhibit a prolonged gadolinium elimination half-life.

 

To date, the only known adverse health effect related to gadolinium retention is a rare condition called nephrogenic systemic fibrosis (NSF). NSF is a relatively uncommon condition in which fibrous plaques develop in the dermis and, often, in deeper connective tissues. Reported cases have occurred almost exclusively in patients with severe renal disease, and almost all have been associated with prior use of GBCAs. NSF is a painful skin disease characterized by thickening of the skin, which can involve the joints and cause significant limitation of motion within weeks to months. Over the past decade, changes in clinical practice guidelines have almost completely eliminated the incidence of NSF. However, the association of NSF and observed elevated gadolinium concentrations is still not fully understood.

Test Classification

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 U.S. Food and Drug Administration.

Urine Preservative Collection Options

Ambient

Yes

Refrigerated

Preferred

Frozen

Yes

6N HCl

Yes

50% Acetic Acid

No

Na2CO3

No

Toluene

Yes

6N HNO3

Yes

Boric Acid

No

Thymol

No