Gadolinium/Creatinine Ratio, Random, Urine
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
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.
An aid in documenting past exposure to gadolinium-containing chelates and to monitor the effectiveness of dialysis
Elevated gadolinium (>0.5 mcg/g creatinine) observed in a random urine specimen collected >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 <0.5 mcg/g creatinine; 95% of unexposed patients will have values <0.1 mcg/g creatinine. The lower limit of detection is 0.1 mcg/g creatinine.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Urine gadolinium concentration may be elevated if the specimen is collected <96 hours of 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 (NSF).
Evaluation of urine for gadolinium content has minimal value in making the diagnosis of NSF. Gadolinium is 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.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
0.0-0.4 mcg/g Creatinine
Reference values apply to all ages.
Clinical References Provides recommendations for further in-depth reading of a clinical nature
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