Lever
Lifestyle
- Regular exercise
- Adequate hydration
- Smoking cessation
Blutwerte · Marker
Cystatin C
Cystatin C · CysC
Nierenwerte
- Einheit:
- mg/L
- Abbreviation
- CysC
Cystatin C measures the concentration of a cysteine protease inhibitor in the blood, reflecting glomerular filtration rate (GFR) and kidney function.
Reference Ranges
Reference
0.6–1.2mg/L
0.6
0.9
1.2
LowNormalHigh
Reference
Optimal
Unit · mg/LReference ranges can vary slightly based on age and sex. Generally, Cystatin C is less influenced by muscle mass compared to creatinine.
Overview
Übersicht
Cystatin C (CysC) is a low molecular weight cysteine protease inhibitor produced by all nucleated cells. It is freely filtered by the glomeruli in the kidneys and reabsorbed and catabolized by the renal tubular cells, making it a reliable marker for estimating glomerular filtration rate (GFR). Researchers have found that CysC is a more sensitive and earlier indicator of kidney function decline compared to traditional markers like serum creatinine, particularly in individuals with mild to moderate renal impairment. Clinically, elevated levels of Cystatin C are indicative of reduced kidney function and are associated with chronic kidney disease (CKD), cardiovascular diseases, and cerebrovascular disorders. It also plays a role in inflammation and autophagy, which may be relevant in the context of atherosclerosis and hypertension. For athletes and biohackers, monitoring Cystatin C can provide insights into kidney health, which is crucial for maintaining optimal performance and longevity. However, the use of Cystatin C as a biomarker requires consideration of potential confounders such as age, sex, and body composition. Researchers have observed that while CysC is less affected by muscle mass compared to creatinine, factors like inflammation and thyroid function can influence its levels. Therefore, it is important to interpret Cystatin C levels in conjunction with other clinical parameters and biomarkers.
Klinische Bedeutung
Elevated Cystatin C levels indicate impaired kidney function and are associated with chronic kidney disease, cardiovascular diseases, and increased risk of cerebrovascular disorders. Reduced levels are uncommon and typically not clinically significant.
Dynamics
Trend Interpretation
Rising Values
Progressively rising Cystatin C values suggest worsening kidney function. Re-test in 4-6 weeks if levels are outside the normal range.
Falling Values
Falling values may indicate improved kidney function or resolution of an acute condition.
Re-test Interval
4 weeks if outside optimal range
Etiology
Causes — High & Low
Cause
Elevated Levels
- Chronic kidney disease
- Cardiovascular disease
- Cerebrovascular disorders
- Inflammation
- Hypertension
Cause
Low Levels
- Overhydration
- Hyperthyroidism
- Low muscle mass
- Pregnancy
Protocol
How to Optimize
Lever
Nutrition
- Low-sodium diet
- Adequate protein intake
Note:
Consult a healthcare provider before making significant lifestyle or dietary changes, especially if kidney function is impaired.
Testing Guidelines
✓Fasting Not Required
✓Not Time-Sensitive
Testing Frequency
Annually for individuals with risk factors for kidney disease, more frequently if CKD is diagnosed.
Interfering Factors
- Thyroid dysfunction
- Inflammatory conditions
Related Peptides & Hormones
Creatinine
hormone or peptideCorrelated with
Open Research Questions
Current research suggests that the transition of all reagents and estimated GFR equations to the newly established International Standard for cystatin C is critical for developing generalizable data, yet reference ranges and optimal targets remain debated. Researchers have not yet established the impact of confounding factors such as inflammation and comorbidities on cystatin C levels in various populations. Additionally, clinical questions regarding the frequency of cystatin C monitoring in CKD patients remain unanswered.
31 Research Publications
1,058
Total Citations
11
Human/RCT
3.3
Avg. Influence
2025
Latest
Sort
Filter
01Top
#01
Creatinine: From physiology to clinical application.
ReviewInfluence12.0
399
This review examined the challenges of accurately estimating kidney function using serum creatinine and discussed its limitations. Researchers found that understanding these limitations is crucial for interpreting creatinine values and identifying alternative biomarkers for kidney function assessment.
02Top
#02
Cystatin C as a biomarker of chronic kidney disease: latest developments.
ReviewInfluence8.0
187
This study examined the role of cystatin C as a biomarker for chronic kidney disease (CKD). Researchers found that cystatin C is an early and accurate indicator of CKD, particularly useful when traditional markers like creatinine are inadequate. The study emphasizes the need for standardized measurement methods to enhance its clinical application.
03Top
#03
Cystatin C: a kidney function biomarker.
Onopiuk Anna, et al. · Advances in clinical chemistry · 2015
ReviewInfluence3.0
157
Researchers found that cystatin C is a useful marker for assessing glomerular filtration rate (GFR) due to its independence from factors like age and muscle mass. The study discusses its structure, function, and methods for measurement.
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
53
This study explored the characteristics of serum creatinine and cystatin C as renal biomarkers for estimating glomerular filtration rate (eGFR). Researchers observed that both biomarkers have distinct advantages and disadvantages, and their clinical utility varies based on age-dependent reference intervals.
05
#05
Cystatin C: A Primer for Pharmacists.
ReviewInfluence4.0
47
Researchers found that cystatin C can serve as an alternative to serum creatinine for evaluating kidney function, particularly in medication management. The study emphasizes the need for pharmacists to understand the strengths and limitations of cystatin C in various patient populations.
06
#06
Cystatin C is ready for clinical use.
ReviewInfluence4.0
46
Researchers reviewed the clinical benefits of using cystatin C as an alternative biomarker for glomerular filtration rate (GFR). They found that cystatin C provides more accurate GFR estimates, especially in acutely ill patients.
07
#07
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.
08
#08
Biomarkers for sarcopenia, muscle mass, muscle strength, and physical performance: an umbrella review.
Liu Gaoming, et al. · Journal of translational medicine · 2025
Meta-AnalysisInfluence1.0
35
This umbrella review identified various biomarkers associated with sarcopenia, including the creatinine to cystatin C ratio. Researchers found that this ratio demonstrated 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.
09
#09
Role of cystatin C in urogenital malignancy.
ReviewInfluence1.0
23
This study reviewed the role of cystatin C in urogenital malignancies, suggesting it may serve as a promising biomarker for early tumor detection and prognosis. Researchers highlighted the need for further investigation into its clinical applications.
10
#10
Cystatin C in Cerebrovascular Disorders.
Zhang Yaru & Sun Li · Current neurovascular research · 2017
ReviewInfluence1.0
22
Researchers found that cystatin C is a sensitive biomarker for predicting kidney function and may also play a significant role in various cerebrovascular disorders. The study discusses four mechanisms by which cystatin C may influence cerebrovascular diseases, highlighting its potential as a novel biomarker.
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.
Clinical Trials (17)
17
Total Trials
3,391
Total Enrolled
A Pragmatic Clinical Trial Comparing the Risk of Acute Kidney Injury During Treatment With Vancomycin and Piperacillin-Tazobactam vs. Vancomycin and Cefepime in Hospitalized Patients
Sponsor
University of Pennsylvania
Enrollment
750
Started
2026
Primary outcome
Serum Cystatin C Concentration
Acute Kidney Injury
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
Evaluating the Incidence of Pseudo-Acute Kidney Injuries in Patients With Metastatic Breast Cancer on CDK4/6 Inhibitors Trough Cystatin C Analysis
NCT06338605UNKNOWN
Sponsor
Erasmus Medical Center
Enrollment
40
Started
2023
Primary outcome
Pseudo-AKI in patients on CDK4/6 inhibitors
Advanced Breast Cancer
Prognostic Value of Myosteatosis and Creatinine-to-cystatin C Ratio in Patients With Pancreatic Ductal Adenocarcinoma
NCT05584852UNKNOWN
Sponsor
The Affiliated Hospital of Qingdao University
Enrollment
240
Started
2022
Primary outcome
overall survival
Skeletal Muscle RadiodensityMyosteatosisScr/CysC RatioPancreatic Ductal Adenocarcinoma
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
Comparison Between Different Anaesthesia Techniques Protecting Renal Function in Children Undergoing Radicle Nephrectomy
Sponsor
Alexandria University
Enrollment
75
Started
2021
Primary outcome
cystatin C
Renal InjuryChild, Only
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
Improved Estimation of GFR by Cystatin C in Preventing Contrast Induced Nephropathy by NAC or Zn
NCT00399256TERMINATED
Sponsor
Robert Bosch Gesellschaft für Medizinische Forschung mbH (RBMF)
Enrollment
60
Started
2004
Primary outcome
Incidence of acute renal failure
Chronic Kidney Failure
Publication Trend
Research publications about Cystatin C over time
6totalTrack 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