eGFR Creatinine-Cystatin C Calculation With Albumin:Creatinine Ratio, Urine
Use
An estimated 37 million U.S. adults have chronic kidney disease (CKD). In addition to cardiovascular-associated events, they are at risk for kidney failure or end-stage kidney disease (ESKD) requiring dialysis or kidney transplant. In the 2015-2016 National Health and Nutrition Examination Survey, prevalence of CKD stages G1-4 was 14.2% among adult participants. One in three U.S. adults is at risk for CKD due to prevalent risk factors such as diabetes and/or high blood pressure. The incidence of CKD is projected to increase during the next 20 years because of increasing obesity rates and an aging U.S. population.1
Special Instructions
Ensure proper specimen collection; separate plasma from red blood cells if using a green-top (heparin) tube and transfer to a transfer tube. Collect random urine without preservatives, with pH between 4-8. Sample stability is crucial for accurate results, with specific temperature and time requirements.
Limitations
Cystatin C levels are not influenced by muscle mass or nutrition, unlike creatinine values. It becomes a more reliable marker in certain conditions where creatinine may be affected. A creatinine rise indicates a significant GFR reduction, usually by about 50%. This test cannot substitute comprehensive kidney assessment, especially where other kidney injury etiologies exist and may not be detected by urine albumin alone.
Methodology
Other
Biomarkers
LOINC Codes
- 98979-8
- 2160-0
- 33863-2
- 98980-6
- 2161-8
- 14957-5
- 9318-7
Result Turnaround Time
2-5 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1.5 mL
Minimum Volume
1 mL
Container
Gel-barrier tube or green-top (heparin) tube
Collection Instructions
If green-top (heparin) tube is used, separate plasma from red blood cells and transfer plasma to a transfer tube.
Storage Instructions
Room temperature
Causes for Rejection
Specimen other than serum or heparinized plasma; grossly hemolyzed (>1,000 mg/dL Hgb) samples; excessive turbidity and clots in samples or bloody urine
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 7 days at 15°C to 25°C |
| Refrigerated | 7 days at 2°C to 8°C |
| Frozen | 14 days at -25°C |