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Cystatin C as part of better kidney care

Written by Kristin Hart | Mar 10, 2022 8:20:26 AM

World Kidney Day 2022 – Kidney Health for All

World Kidney Day is a global campaign taking place March 10th every year. This year the theme is “Kidney Health for All - Bridge the gap to better kidney care”. World Kidney Day's objective is to raise awareness globally of the importance of Kidney Health and to increase screening for chronic kidney disease (CKD).

Chronic kidney disease (CKD) is common and harmful: 1 out of 10 adult people worldwide have it, and if left untreated it can be deadly. While early detection allows for disease care and management to help prevent morbidity and mortality, and improve cost effectiveness and sustainability, kidney disease related mortality continues to increase yearly and is projected to be the 5th leading cause of death by 2040.


Unbiased assessment of kidney function and eGFR

Biomarkers can be used to screen for, diagnose, or monitor disease activity. CKD will typically evolve over several years and will often have a long latent period. The diagnosis, evaluation and treatment of CKD are therefore mostly based on biomarkers that can assess the glomerular filtration rate (GFR) and kidney function.

Cystatin C is a kidney marker that is less susceptible to factors that affect muscle mass (age, diet, sex, physical activity, etc.)1,2, as it is expressed through all nucleated cells. Individuals with similar kidney function can therefore be expected to have similar serum concentrations of cystatin C. Creatinine, another kidney marker which is widely used, is released by skeletal muscles as a by-product of muscle metabolism. Consequently, individuals with varying muscle mass but the same kidney function have different serum concentrations of creatinine and therefore different creatinine-based eGFRs.


Task force recommends increasing the use of cystatin C combined with creatinine

Analysing cystatin C and creatinine together can give the physician more accurate information on the patient’s eGFR than creatinine alone3 This is the background for The National Kidney Foundation (NKF) in the US and the American Society of Nephrology (ASN) in a joint taskforce, recently recommended increasing the use of cystatin C combined with serum (blood) creatinine4, as a confirmatory assessment of GFR or kidney function, as part of a race-free approach to diagnosing kidney disease and to secure unbiased diagnostics. In the US a disproportionate number of the 37 million Americans that have kidney disease are of African American, Hispanic, Asian, or Native American descent. The use of race modifiers in the clinical creatinine based eGFR equations previously used to detect and manage kidney disease have contributed to major kidney-health disparities among these ethnic minority groups, which the increased use of cystatin C can help reduce.


The clinical value of cystatin C

  • Independent of protein intake, gender, ethnicity, age and muscle mass1,2,5
  • Superior to creatinine-based equations in predicting end-stage renal disease, cardiovascular manifestations, hospitalisation and death2
  • Cystatin C based drug-specific dosing protocols can be beneficial in treatment with prescribed medications that are renally eliminated and/or nephrotoxic6

Gentian’s cystatin C immunoassay

Gentian’s cystatin C immunoassay was launched in 2006. The assay is FDA510(k) cleared since 2008 and CE-marked. It is a Particle-Enhanced Turbidimetric Immunoassay (PETIA) for in vitro testing of cystatin C in human plasma and serum samples. The test has documented high inter-instrument accuracy on a wide range of clinical chemistry analysers.

 

Explore cystatin C in your lab

If you and your colleagues would like to learn more about cystatin C and how you could incorporate this test into clinical workflows within your organisation, please contact us via marketing@gentian.com or the form below:

 

References:

  1. Tangri N et al. Changes in dietary protein intake has no effect on serum cystatin C levels independent of the glomerular filtration rateKidney Int. 2011
  2. Grubb A. Cystatin C is Indispensable for Evaluation of Kidney DiseaseEJIFCC. 2017
  3. Inker LA et al. New Creatinine- and Cystatin C-Based Equations to Estimate GFR without Race. N Engl J Med. 2021
  4. https://www.asn-online.org/about/press/releases/ASN_PR_20210923_eGFR.Task.Force.Pre.pdf
  5. KDIGO Guidelines 2012 published in Kidney International Supplements Vol3 Issue 1, Jan 2013
  6. Barreto EF et al. Prediction of the Renal Elimination of Drugs With Cystatin C vs Creatinine: A Systematic ReviewMayo Clin Proc. 2019