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Test Code GDCRU Gadolinium/Creatinine Ratio, Random, Urine

Performing Laboratory

Mayo Medical Laboratories in Rochester

Reporting Name

Gadolinium/Creat Ratio, Random, U

Specimen Type

Urine


Specimen Required


Supplies: Urine Tubes, 10 mL (T068)

Collection Container/Tube: Clean, plastic urine collection container

Submission Container/Tube: Plastic, 10-mL urine tube (T068) 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 Trace Metals Analysis Specimen Collection and Transport in Special Instructions for complete instructions.


Reject Due To

Hemolysis

NA

Lipemia

NA

Icterus

NA

Other

NA

Specimen Stability Information

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

Specimen Minimum Volume

0.7 mL

Day(s) and Time(s) Performed

Wednesday; 8 a.m.

Specimen Retention Time

14 days

Analytic Time

1 day

Reference Values

0-17 years: not established

≥18 years: <0.8 mcg/g creatinine

Useful For

An aid in documenting past exposure to gadolinium-containing chelates and to monitor the effectiveness of dialysis

Method Name

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

CDCR: Enzymatic Colorimetric Assay

Test Classification

See Individual Test IDs

CPT Code Information

83018 Gadolinium Concentration

82570 Creatinine Concentration

LOINC Code Information

Test ID Test Order Name Order LOINC Value
GDCRU Gadolinium/Creat Ratio, Random, U In Process

 

Result ID Test Result Name Result LOINC Value
CDCR Creatinine Conc 2161-8
32873 Gadolinium/Creat Ratio, U Unable to Verify

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 for magnetic resonance imaging and computer tomography scanning.

 

Gadolinium is eliminated primarily by renal filtration. In healthy subjects with normal renal function, the plasma half-life of gadolinium is approximately 90 minutes. Patients with reduced renal function exhibit an increased gadolinium excretion half-life.

 

Gadolinium has been associated with the nephrogenic systemic fibrosis in patients with impaired renal function. In this syndrome, prolonged retention of gadolinium is thought to allow the gadolinium cation to dissociate from its synthetic organic chelator and deposit predominantly in the skin, although other organs may be affected as well. These patients are often severely debilitated by progressive skin thickening and tightening. Fibrosis of skeletal muscle, lungs, liver, testes, and myocardium have all been observed, often with fatal results. Because the ionic radius of gadolinium (3+) is similar to that of calcium (2+), it may also deposit in bone.

 

Three hemodialysis treatments are required to substantially remove gadolinium from patients with impaired renal function; peritoneal dialysis is not effective.

Interpretation

Elevated gadolinium (>0.7 mcg/g creatinine) observed in a random urine specimen collected more than 96 hours after administration of gadolinium-containing contrast media may indicate impaired ability to eliminate gadolinium or continued exposure, suggesting either reduced renal function or exposure to anthropogenic sources. Patients with reduced renal function who have been exposed to gadolinium may have an increased risk to develop nephrogenic systemic fibrosis.

 

The normal value is less than 0.8 mcg/g creatinine; 95% of unexposed patients will have values below 0.1 mcg/g creatinine. The lower limit of detection is 0.1 mcg/g creatinine.

Clinical Reference

1. D'Hease P, De Broe M: Gadolinium. In Handbook on Metals in Clinical and Analytical Chemistry. Edited by HG Seiler, A Sigel, H Sigel. Marcel Dekker, Inc, New York, 1994, pp 365-369 

2. Swan SK, Lambrecht LJ, Townsend R, et al: Safety and pharmacokinetic profile of gadobenate dimeglumine in subjects with renal impairment. Invest Radiol 1999;34:443-448 

3. Otherson JB, Maize JC, Woolson RF, Budisavljevic MN: Nephrogenic systemic fibrosis after exposure to gadolinium in patients with renal failure. Nephrol Dial Transplant 2007;10:1093-1100

4. Perazella MA: Nephrogenic systemic fibrosis, kidney disease, and gadolinium: is there a link? Clin J AM Soc Nephrol 2007;2:200-202

5. Saitoh T, Hayasaka K, Tanaka Y, et al: Dialyzability of gadodiamide in hemodialysis patients. Radiat Med 2006;24:445-451

6. 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

7. Girardi M, Kay J, Elston DM, et al: Nephrogenic systemic fibrosis: Clinicopathological definition and workup recommendations. J Am Acad Dermatol 2011;65:1095-1106

8. Telgmann L, Sperling M, Karst U: Determination of gadolinium-based MRI contrast agents in biological and environmental samples: A review. Analytica Chimica Acta 2013;764:1-16

Method Description

Gadolinium (Gd) 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)

 

Creatinine enzymatic method is based on the determination of sarcosine from creatinine with the aid of creatininase, creatinase, and sarcosine oxidase. The liberated hydrogen peroxide is measured via a modified Trinder reaction using a colorimetric indicator. Optimization of the buffer system and the colorimetric indicator enables the creatinine concentration to be quantified both precisely and specifically.(Package insert: Roche Diagnostics, Indianapolis IN, 2004)

Profile Information

Test ID Reporting Name Available Separately Always Performed
GDCR Gadolinium/Creat Ratio, U No Yes
CDCR Creatinine Conc No Yes

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/g creatinine (median value 0.2 mcg/g creatinine) with no evidence of age or gender trend. Urine gadolinium concentrations observed in Mayo Clinic patients with nephrogenic systemic fibrosis (NSF), either before or after chelation therapy with succimer, were in the range of 2 to 5 mcg/g creatinine (ie, succimer had no effect on excretion rate). No peer-reviewed reports of urine gadolinium concentrations associated with NSF were found on literature search.