eGFR Creatinine-Cystatin C Calculation
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
The Kidney Disease: Improving Global Outcomes (KDIGO) clinical practice guidelines suggest measurement of cystatin C, an alternative endogenous filtration marker, in specific circumstances when GFR estimates based on serum creatinine are thought to be less accurate.
Limitations
Cystatin C has not been shown to be affected by factors such as muscle mass and nutrition, factors which have been demonstrated to affect creatinine values. In addition, a rise in creatinine does not become evident until the GFR has fallen by approximately 50%.
Methodology
Other
Biomarkers
LOINC Codes
- 98980-6
- 2160-0
- 33863-2
- 98980-6
- 98979-8
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
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 |