Use of Cystatin C to Assess Kidney Function
This slide shows the eGFR equation that was developed in the MDRD study, and is most commonly reported by lab information systems. The key demographic variables are age, gender, and race. Shown is the equation one would use for serum creatinines measured by an enzymatic creatinine assay that is traceable to isotope dilution- mass spectrometry standards. There is a slightly different equation that would be applied if a lab was using certain Jaffe creatinine assays. Since the MDRD eGFR equation does not perform well in persons with normal kidney function, most labs do not report an actual number unless it is less than 60 mL per minute per 1.73 m2. Furthermore, the lab often does not have information regarding a person’s race. Therefore, most labs report 2 numbers: 1 for African Americans and 1 for non-African Americans. Finally, the MDRD equation has not yet been validated for persons over 70 years old, and therefore many labs do not report any eGFR results for older individuals.
Revised eGFR Equation (ID-MS version)
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- 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