Creatinine, Random, Urine
Use
The test is useful for normalizing urinary analytes to account for the variation in urinary concentrations between individuals when using random urine collections. Creatinine is formed from the metabolism of creatine and phosphocreatine, which are primarily found in muscle. Since creatinine is freely filtered by glomeruli and fully excreted in the urine, it provides an estimate of glomerular filtration rate. Thus, creatinine concentration can reflect overall urinary concentration, helping to normalize other analytes in a random urine specimen.
Special Instructions
This test is not orderable as a standalone test and must be ordered as part of a profile, which can include other tests such as RLTE4 - Leukotriene E4, Random, Urine, and TIUCR - Titanium/Creatinine Ratio, Random, Urine.
Limitations
The intraindividual variability in creatinine excretion can be due to differences in muscle mass or dietary protein intake, especially cooked meat, affecting urinary creatinine levels. Acute changes in glomerular filtration rate before a steady state can alter the amount of urinary creatinine excreted. Incorrect specimen handling can lead to diagnostic confusion.
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, 5-mL tube
Collection Instructions
1. Collect a random urine specimen. 2. No preservative.
Storage Instructions
Frozen (preferred): 30 days; Ambient: 14 days; Refrigerated: 30 days.
Causes for Rejection
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 14 days |
| Refrigerated | 30 days |
| Frozen | 30 days |