Test ID: GDU    
Gadolinium, 24 Hour, Urine

As an aid in the diagnosis of nephrogenic systemic fibrosis

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 the 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 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 also 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 patents with impaired renal function; peritoneal dialysis is not effective.

0.0-0.4 mcg/specimen

Reference values apply to all ages.

Elevated gadolinium (>0.5 mcg/specimen) observed in a 24-hour urine specimen collected >48 hours after administration of gadolinium-containing contrast media indicates impaired ability to eliminate gadolinium. These patients have an increased risk of developing nephrogenic systemic fibrosis (NSF).

Elevated gadolinium in a specimen collected <48 hours after contrast media infusion does not indicate risk of NSF.

A normal value is <0.5 mcg/specimen; the lower limit of the assay's reportable range is 0.1 mcg/specimen.

Urine gadolinium concentration will be elevated if the specimen is collected <96 hours after administration of gadolinium-containing contrast media. This elevation is due to residual gadolinium present from contrast media infusion. Elevated gadolinium in a specimen collected <96 hours after contrast media infusion does not indicate risk of nephrogenic systemic fibrosis.

An evaluation of urine gadolinium concentration in 100 unexposed, healthy human subjects generated a reference range of >0.1 to 0.5 mcg/24-hour (median value 0.2 mcg/24 hour) 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 mcg/L/24-hour to 5 mcg/24-hour (ie, succimer had no effect on excretion rate). No peer-reviewed reports of urine gadolinium concentrations in NSF were found on literature search.

Gadolinium (Gd[3+]) has an atomic mass of 157.25 g/mole.

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;2:309-311

• Urine Preservatives
• Metals Analysis-Collection and Transport