Creatinine With eGFR
Also known as: GFR EST
Use
This test is used to evaluate kidney function by measuring the level of creatinine in serum or plasma and estimating the glomerular filtration rate (eGFR) using the CKD-EPI equation. The eGFR is adjusted for a body surface area of 1.73 square meters and provides an assessment of kidney filtration function. This is useful in diagnosing and monitoring acute kidney injury, chronic kidney disease, and acute glomerular damage. It is most accurate in individuals 18 years and older and less reliable in patients with unusual muscle mass or those on specific medications affecting creatinine metabolism.
Special Instructions
Patient age and sex are required for accurate eGFR calculation using the CKD-EPI formula. Specimens must be separated from cells immediately or within two hours of collection to ensure reliability.
Limitations
The creatinine-based eGFR is less accurate in individuals at extremes of muscle mass or those who have restricted protein intake, consume creatine supplements, undergo extra-renal metabolism of creatinine, or take medications affecting renal tubular secretion of creatinine. Accurate GFR estimation requires consistent day-to-day creatinine levels.
New York Approved
Methodology
Automated Analyzer (Clinical Chemistry)
Biomarkers
LOINC Codes
- 2160-0
- 98979-8
Result Turnaround Time
1 day
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1 mL
Minimum Volume
0.2 mL
Container
ARUP standard transport tube
Collection Instructions
Collect in plasma separator tube or serum separator tube and allow to clot completely at room temperature. Separate serum or plasma from cells ASAP or within 2 hours of collection.
Storage Instructions
Refrigerated
Causes for Rejection
Specimens obtained through catheters infused with hyperalimentation fluid or collected with potassium oxalate/sodium fluoride or sodium citrate.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 1 week |
| Refrigerated | 1 week |
| Frozen | 3 months |