Cystatin C (CyC)
Cystatin C (CyC)
Definition:
Cystatin C (CyC) is a small protein produced by all nucleated cells in the body. It functions as a cysteine protease inhibitor and is filtered out of the blood by the kidneys. The measurement of cystatin C levels in serum is increasingly recognized as a valuable marker for assessing kidney function, particularly in cases where traditional markers like creatinine may be less reliable.
Importance in Kidney Function Assessment:
- Early Detection of Kidney Dysfunction: Cystatin C levels can rise before changes in serum creatinine, making it an earlier indicator of declining kidney function. This characteristic is particularly useful in diagnosing acute kidney injury (AKI) and chronic kidney disease (CKD).
- Less Influenced by Muscle Mass: Unlike creatinine, cystatin C levels are not significantly affected by muscle mass, age, or gender, providing a more stable measure of glomerular filtration rate (GFR).
- Prognostic Value: Elevated cystatin C levels have been associated with increased risk of cardiovascular disease and mortality, making it a critical marker for risk stratification in patients with kidney disease.
Clinical Applications
Cystatin C testing is utilized in various clinical scenarios:
- Diagnosis and Monitoring of CKD: It helps confirm CKD diagnoses and monitor disease progression.
- Assessment of AKI: Cystatin C can detect early renal impairment that may be missed by creatinine measurements.
- Risk Stratification: It aids in evaluating the risk of cardiovascular events and mortality in patients with compromised kidney function.
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References
- Cystatin C as a Biomarker of Chronic Kidney Disease: Latest Developments
This article reviews the clinical utility of cystatin C as a biomarker for CKD, emphasizing its advantages over traditional markers.
DOI: 10.3390/ijms21197149 - Serum Cystatin C as a Marker of Renal Function in Detection of Early Acute Kidney Injury
This study highlights the sensitivity of cystatin C in identifying early kidney dysfunction compared to serum creatinine levels.
DOI: 10.1177/17562872211008492 - Advantages, Limitations, and Clinical Considerations in Using Cystatin C
This article discusses the reliability and accuracy of cystatin C as a marker for kidney function across diverse populations.
DOI: 10.34067/KID.0003202022 - Assessment of Cystatin C Level for Risk Stratification in Adults With Chronic Kidney Disease
This cohort study assesses how cystatin C can better stratify risk for cardiovascular disease and mortality compared to creatinine-based estimates.
DOI: 10.1001/jamanetworkopen.2022.97627
