Test ID GDCRU Gadolinium/Creatinine Ratio, Random, Urine
Useful For
An aid in documenting past exposure to gadolinium-containing chelates and to monitor the effectiveness of dialysis
Profile Information
Test ID | Reporting Name | Available Separately | Always Performed |
---|---|---|---|
GDCR | Gadolinium/Creat Ratio, U | No | Yes |
CDCR | Creatinine Conc | No | Yes |
Special Instructions
Method Name
GDCR: Inductively Coupled Plasma-Mass Spectrometry (ICP-MS)
CDCR: Enzymatic Colorimetric Assay
Reporting Name
Gadolinium/Creat Ratio, Random, USpecimen Type
UrineCollection Container/Tube: Clean, plastic urine collection container
Submission Container/Tube: Plastic, 10-mL urine tube (Supply 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.
Specimen Minimum Volume
0.7 mL
Specimen Stability Information
Specimen Type | Temperature | Time |
---|---|---|
Urine | Refrigerated (preferred) | 28 days |
Ambient | 28 days | |
Frozen | 28 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 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.
Reference Values
0.0-0.4 mcg/g Creatinine
Reference values apply to all ages.
Cautions
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.
Day(s) Performed
Wednesday; 8 a.m.
Report Available
1 dayPerforming Laboratory

Test Classification
See Individual Test IDsCPT Code Information
83018-Gadolinium/creatinine ratio