Lever
Lifestyle
- Regular exercise
- Adequate hydration
- Avoidance of nephrotoxic substances
Blutwerte · Marker
Cystatin C
Cystatin C · CysC
Nierenwerte
- Einheit:
- mg/L
- Abbreviation
- CysC
Cystatin C quantifies the level of a cysteine protease inhibitor in the blood, reflecting kidney filtration efficiency.
Reference Ranges
Reference
0.6–1.2mg/L
0.6
1.2
LowNormalHigh
Reference
Unit · mg/LReference ranges may vary slightly by laboratory; generally consistent across sexes and age groups.
Overview
Übersicht
Cystatin C (CysC) is a non-glycosylated protein produced by all nucleated cells and is a potent inhibitor of cysteine proteases. It is freely filtered by the glomeruli and almost completely reabsorbed and catabolized by the proximal renal tubular cells, making it a reliable marker of glomerular filtration rate (GFR). Researchers have found that Cystatin C is less influenced by muscle mass, age, and sex compared to creatinine, making it a more accurate reflection of kidney function, especially in populations where creatinine may be misleading. Clinically, Cystatin C is an important biomarker for chronic kidney disease (CKD) and acute kidney injury (AKI), providing a more sensitive measure of renal function than creatinine alone. It is particularly useful in detecting early stages of CKD and in populations such as neonates, where creatinine levels are confounded by maternal contributions and muscle mass. In the context of athletic performance and biohacking, Cystatin C offers a more precise assessment of kidney health, which is crucial for individuals engaged in high-intensity training or those using supplements that may affect renal function. Longevity enthusiasts may also monitor Cystatin C to ensure optimal kidney health, which is vital for overall health and lifespan. However, researchers observed that factors such as thyroid dysfunction, corticosteroid use, and inflammation can influence Cystatin C levels. It is not significantly affected by fasting or time of day, making it a convenient marker for regular monitoring. Nonetheless, standardization of measurement techniques and equations for estimated GFR (eGFR) using Cystatin C is essential for consistent interpretation across different laboratories.
Klinische Bedeutung
Elevated Cystatin C levels indicate impaired kidney function, often reflecting early stages of chronic kidney disease or acute kidney injury. Reduced levels are generally not clinically significant but may indicate improved kidney function.
Dynamics
Trend Interpretation
Rising Values
Progressively rising Cystatin C levels suggest worsening kidney function. Re-test every 3 months if levels are outside the optimal range.
Falling Values
Progressively falling levels may indicate improving kidney function or recovery from acute kidney injury.
Re-test Interval
3 months if outside optimal range
Etiology
Causes — High & Low
Cause
Elevated Levels
- Chronic kidney disease
- Acute kidney injury
- Thyroid dysfunction
- Corticosteroid use
- Inflammation
Cause
Low Levels
- Improved kidney function
- Overhydration
- Hyperthyroidism
- Increased protein intake
Protocol
How to Optimize
Lever
Nutrition
- Balanced diet with adequate protein
- Reduced sodium intake
Note:
Consult a healthcare provider before making significant lifestyle or dietary changes, especially if kidney function is compromised.
Testing Guidelines
✓Fasting Not Required
✓Not Time-Sensitive
Testing Frequency
Annually for healthy adults, more frequently if monitoring kidney disease.
Interfering Factors
- Thyroid dysfunction
- Corticosteroid use
- Inflammation
Related Peptides & Hormones
Creatinine
hormone or peptideCorrelated with
Open Research Questions
Current research suggests that reference ranges and optimal targets for serum cystatin C in various populations, particularly neonates, remain inadequately defined. Researchers have not yet established standardized criteria for its use in chronic kidney disease versus acute kidney injury contexts. Additionally, clinical questions regarding the long-term implications of cystatin C levels on patient outcomes and the potential confounding effects of factors like inflammation or muscle mass require further investigation.
22 Research Publications
966
Total Citations
7
Human/RCT
3.7
Avg. Influence
2025
Latest
Sort
Filter
01Top
#01
Creatinine: From physiology to clinical application.
ReviewInfluence12.0
390
This review examined the limitations of serum creatinine as a biomarker for kidney function and discussed alternative biomarkers, including cystatin C. Researchers found that understanding these limitations is crucial for accurate kidney function assessment.
02Top
#02
Cystatin C as a biomarker of chronic kidney disease: latest developments.
ReviewInfluence8.0
183
Researchers assessed the utility of serum cystatin C as a biomarker for chronic kidney disease (CKD). They found that cystatin C is an early and accurate indicator of CKD, especially in patients where creatinine is inadequate.
03Top
#03
Cystatin C: a kidney function biomarker.
Onopiuk Anna, et al. · Advances in clinical chemistry · 2015
ReviewInfluence3.0
157
This study discussed the importance of cystatin C as a biomarker for kidney function. Researchers found that cystatin C is a sensitive indicator of glomerular filtration rate and is less influenced by factors like age, gender, and muscle mass, making it a valuable tool for assessing renal function.
Key findings
- 01Cystatin C is a protein that can serve as a more accurate marker for kidney filtration compared to traditional methods.
- 02Its levels remain consistent regardless of age, gender, or muscle mass, which are common variables that can skew results.
- 03The review discusses the biological role of cystatin C and the methods used to measure its concentration in the blood.
04
#04
Exploring Renal Function Assessment: Creatinine, Cystatin C, and Estimated Glomerular Filtration Rate Focused on the European Kidney Function Consortium Equation.
ReviewInfluence1.0
48
This review focused on the use of serum creatinine and cystatin C for estimating glomerular filtration rate (eGFR). Researchers highlighted the advantages and disadvantages of these biomarkers and their clinical utility in kidney damage assessment.
05
#05
Cystatin C: A Primer for Pharmacists.
ReviewInfluence4.0
47
This article provided an overview of cystatin C for pharmacists involved in medication management. Researchers emphasized the importance of cystatin C in evaluating kidney function for drug dosing, noting its advantages over serum creatinine, particularly in specific patient populations.
06
#06
Detecting Neonatal AKI by Serum Cystatin C.
Xu Xin, et al. · Journal of the American Society of Nephrology : JASN · 2023
HumanInfluence5.0
39
In a study of hospitalized neonates, researchers proposed cystatin C-related criteria for detecting acute kidney injury (AKI). They found that cystatin C is a sensitive biomarker for neonatal AKI, identifying significantly more cases than traditional creatinine criteria.
Key findings
- 01Cys-C detected 6.5 times more cases of AKI compared to traditional creatinine criteria.
- 02Neonates identified with AKI by Cys-C alone had a nearly three times higher risk of in-hospital death.
- 03Cys-C levels remained stable across different gestational ages and birth weights, making it a reliable marker.
07
#07
Biomarkers for sarcopenia, muscle mass, muscle strength, and physical performance: an umbrella review.
Liu Gaoming, et al. · Journal of translational medicine · 2025
ReviewInfluence1.0
34
This umbrella review identified biomarkers related to sarcopenia, including the creatinine to cystatin C ratio. Researchers found that this ratio is frequently used and demonstrates moderate diagnostic accuracy for sarcopenia.
Key findings
- 01The creatinine to cystatin C ratio is the most commonly used diagnostic biomarker for sarcopenia, showing moderate accuracy.
- 02Inflammatory biomarkers like interleukin-6 and C-reactive protein were found to be elevated in patients with sarcopenia.
- 03Most biomarkers studied showed weak correlations with sarcopenia, indicating a need for further research.
08
#08
Cystatin C in Cerebrovascular Disorders.
Zhang Yaru & Sun Li · Current neurovascular research · 2017
ReviewInfluence1.0
22
Researchers reviewed the role of cystatin C in cerebrovascular disorders, highlighting its potential as a biomarker. They found that cystatin C is involved in several mechanisms affecting cerebrovascular health, including inflammation and autophagy.
Key findings
- 01Researchers observed that the CysC variant can aggregate and interact with harmful proteins like Amyloid-β.
- 02They found that an imbalance between CysC and certain enzymes may contribute to cerebrovascular issues.
- 03The study noted CysC's role in promoting inflammation and autophagy, which are important in brain health.
09
#09
Role of cystatin C in urogenital malignancy.
ReviewInfluence1.0
20
This review explored the potential role of cystatin C in urogenital malignancies. Researchers found that cystatin C may serve as a promising biomarker for early tumor identification and prognosis. The study emphasizes the need for further investigation into cystatin C's clinical applications in cancer.
10
#10
Urine MMP7 as a kidney injury biomarker.
Review
15
This study reviewed the potential of matrix metalloproteinase 7 (MMP-7) and cystatin C as biomarkers for kidney injury. Researchers found that urinary cystatin C, in combination with MMP-7, could provide insights into tubular injury in kidney diseases, highlighting its diagnostic potential.
Clinical Trials (12)
12
Total Trials
2,226
Total Enrolled
Is Permissive Hypotension Truly Harmless? Early Biomarker Evidence of Subclinical Kidney Injury in Rhinologic Surgery
NCT07328620COMPLETED
Sponsor
Gazi University
Enrollment
35
Started
2025
Primary outcome
Change in serum NGAL and cystatin C concentrations indicating biomarker-defined subclinical renal stress
Acute Kidney InjuryHypotension
Optimization of Beta-lactam Dosing in Critically Ill Patients With Cystatin C (OPTIMIZE-GNI)
Sponsor
National Institute of Allergy and Infectious Diseases (NIAID)
Enrollment
161
Started
2025
Primary outcome
Clearance (Cl)
Bacterial Infection
Kidney Function in People With Cystic Fibrosis in the Era of HEMT
NCT06595420RECRUITING
Sponsor
University of Virginia
Enrollment
260
Started
2025
Primary outcome
Examine whether trajectories of eGFR (calculated from serum creatinine and cystatin C) correlate with urinary kidney injury signatures detected in different urine fractions, or urinary neutrophil levels/activation.
Cystic Fibrosis (CF)Chronic Kidney Disease(CKD)Acute Kidney Injury
Serum Cystatin C for Early Detection of Acute Kidney Injury After Primary Percutaneous Coronary Intervention
NCT06459362NOT_YET_RECRUITING
Sponsor
Assiut University
Enrollment
45
Started
2024
Primary outcome
prevention and screening for early detection of acute kidney injury
Acute Kidney Injury
Phase 2a MIB-626 vs. Placebo COVID-19
Sponsor
Metro International Biotech, LLC
Enrollment
42
Started
2021
Primary outcome
Change from baseline in serum cystatin C levels
Covid19Stage 1 Acute Kidney Injury
Role of Biomarkers in Predicting Contrast-induced Acute Kidney Injury in Critically Ill Patients
NCT02430844COMPLETED
Sponsor
Sanjay Gandhi Postgraduate Institute of Medical Sciences
Enrollment
85
Started
2015
Primary outcome
To analyse the role of plasma and urinary biomarkers (Neutrophil Gelatinase-Associated Lipocalin (NGAL), Cystatin C and Kidney Injury Molecule-1) in predicting contrast-induced acute kidney injury (CI-AKI) in critically ill patients.
Acute Kidney Injury
Cystatin C and Uncontrolled Hypertension
NCT02334033COMPLETED
Sponsor
Ankara University
Enrollment
903
Started
2014
Primary outcome
The prevalence of uncontrolled hypertension
Uncontrolled Hypertension
Description of the Cystatin C as an Early Nephrotoxic Bio-marker in Pediatric Oncology
NCT02822404COMPLETED
Sponsor
University Hospital, Toulouse
Enrollment
42
Started
2012
Primary outcome
Urinary cystatin C rate
Kidney Diseases
Comparison of Markers of Kidney Function
NCT01403766COMPLETED
Sponsor
University of California, Los Angeles
Enrollment
17
Started
2011
Primary outcome
The primary outcome measure is a comparison of determination of GFR through three methods: cystatin C (Gentian assay), creatinine (Schwartz and update Schwartz) and iohexol disappearance
Chronic Kidney DiseaseRenal Insufficiency
Plasma Cystatin C and Acute Kidney Injury
NCT01652755UNKNOWN
Sponsor
Jinhua Central Hospital
Enrollment
100
Started
2011
Acute Kidney Injury
Evaluating the Role of Cystatin C and Creatinine as Markers of Renal Recovery in Critically Ill Patients After Acute Kidney Injury.
NCT02894164COMPLETED
Sponsor
Karolinska Institutet
Enrollment
336
Started
2008
Primary outcome
Renal function
Acute Kidney InjuryChronic Kidney DiseaseAcute Kidney Disease
Assessment of Serum Cystatin C as a Marker of Kidney Function in Children
NCT00300066COMPLETED
Sponsor
Aalborg University Hospital
Enrollment
200
Started
2006
Kidney Disease
Publication Trend
Research publications about Cystatin C over time
7totalTrack your bloodwork in PepStack
Log lab results, track trends and optimize your biomarkers over time.
Legal Disclaimer
This page is for informational and research purposes only. All information is based on published scientific literature and does not constitute medical advice, diagnosis, or treatment recommendations. Many substances listed may not be approved for human use and may be subject to drug regulation laws (e.g., AMG in Germany, FDA in the US). PepStack does not encourage the use of any substance on humans. Always consult a qualified healthcare professional before making any health-related decisions. Use of this information is entirely at your own risk. PepStack assumes no liability for the accuracy, completeness, or timeliness of the content provided. Full disclaimer