Creatinine, Urine
Use
Creatinine is formed from the metabolism of creatine and phosphocreatine, primarily found in muscle. Its production reflects an individual's muscle mass and is relatively constant. Creatinine is freely filtered by the glomeruli, and its excretion helps estimate the glomerular filtration rate (GFR). The concentration of creatinine in urine indicates overall urinary concentration, meaning it can be used to normalize other analytes in a random urine specimen. It is useful for adjusting for variation in urine concentration in random collections.
Special Instructions
Only orderable as part of a profile. This test is included in profiles like ALBR/Albumin, Random, Urine and RALB/Albumin, Random, Urine.
Limitations
Intra-individual variability in creatinine excretion due to muscle mass or meat consumption can affect results. Acute changes in glomerular filtration rate can also alter urinary creatinine excretion before a steady state is developed. The test has not been cleared or approved by the FDA, and it relies on methods modified by Mayo Clinic to determine performance characteristics.
New York Approved
Methodology
Automated Analyzer (Clinical Chemistry)
Biomarkers
LOINC Codes
- 2161-8
- 2161-8
Result Turnaround Time
1 day
Related Documents
For more information, please review the documents below
Specimen
Urine
Volume
5 mL
Minimum Volume
1 mL
Container
Plastic tube
Collection Instructions
Collect a random urine specimen. No preservative.
Causes for Rejection
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 30 days |
| Refrigerated | 30 days |
| Frozen | 30 days |