Creatinine Clearance, Serum and 24-Hour Urine
Use
The Creatinine Clearance test measures the efficiency of the kidneys in filtering creatinine, which can be used to estimate the glomerular filtration rate (GFR). This test is useful for diagnosing and monitoring kidney function and is particularly important for patients with risk factors for chronic kidney disease such as diabetes, hypertension, cardiovascular disease, or a family history of kidney disease. The estimated GFR is calculated using the CKD-EPI equation which does not require adjustments for weight, height, or race, making it widely applicable.
Special Instructions
24-hour urine collection is required along with a serum sample. The serum must be collected within 72 hours before or after the urine collection. Patient's height and weight are also required for accurate interpretation.
Limitations
Creatinine clearance may overestimate true glomerular filtration rate (GFR) by 10% to 15% due to proximal tubular secretion of creatinine. Accuracy is highly dependent on complete and accurately timed urine collection. Results can be skewed in patients with elevated levels of certain substances, such as N-acetyl-p-benzoquinone imine (a metabolite of acetaminophen), N-acetylcysteine, and metamizole.
FDA ApprovedNew York Approved
Methodology
Automated Analyzer (Clinical Chemistry)
Biomarkers
LOINC Codes
- 58446-6
- 20624-3
- 13362-9
- 3167-4
- 12195-4
- 2160-0
- 98979-8
Result Turnaround Time
1-2 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1 mL
Minimum Volume
0.5 mL
Container
Serum gel (preferred) or Red top
Collection Instructions
Centrifuge and aliquot serum into plastic vial. Label specimen as serum.
Causes for Rejection
Gross hemolysis, gross lipemia
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | preferred |
| Refrigerated | preferred |
| Frozen | OK |