Use of Cystatin C to Assess Kidney Function
At this point let us take a step back and ask ourselves a little bit about kidney function. It is important to remember what it is that the kidneys do for us. The quick answer is that they filter blood in order to remove various toxins and waste products of daily metabolism. It is helpful to have a general idea about the amount of filtrating that the kidneys do on a daily basis. It turns out that this number is about 100 L/ day in a healthy individual. It is also helpful to compare this number to our daily urine output, which is much less. A typical number here would be 1 to 3 L. It is important to note that the kidneys filter almost 100 times as much as the amount of fluid that we need to get rid of and that large amount of filtrate is very highly processed to produce our final urine. That daily filtrate, also known as glomerular filtration rate or GFR, is the single best indicator of kidney function and kidney reserve. When GFR falls below certain thresholds, health is impacted.
What do the kidneys do?
Jump to section:
- A Case
- What do the kidneys do?
- Why Measure Renal Function?
- How Is Chronic Kidney Disease (CKD) Defined?
- Stages of Chronic Kidney Disease
- Laboratory Assessment of Kidney Function: What Can We Measure?
- Creatinine as a Marker of GFR
- Creatinine as a Marker of GFR: It Works But...
- How Can We Turn the Serum Creatinine Into a Better Estimate of GFR?
- Revised eGFR Equation (ID-MS version)
- eGFR Equation Works, But it's Not Perfect
- What About Cystatin C?
- Mayo Renal Laboratory Cystatin C By Particle Enhanced Turbidometric Immunoassay (PETIA)
- Comparison To Current Nephelometric Assay (PENIA) Reveals 23% Bias
- Cystatin C PENIA Assay Shift (19%)
- Cystatin C eGFR Using Published Equation* Performs Well3
- Cystatin C Equations Categorize Patients Slightly Better Than MDRD eGFR
- Cystatin C Reference Range
- PETIA Cystatin C Reference Range
- Cystatin C: Useful To Confirm Those At Risk Of CKD Progression And Its Complications (REGARDS)4
- Cystatin C: CKD Progression and Complications (MESA and CHS)5
- Cystatin C in the Acute Hospitalized Setting6
- Back to Our Patient
- Potential Interventions