Cystatin C: why clinical laboratories should be measuring it

Area of Science:

• Biochemistry
• Nephrology
• Clinical Diagnostics

Background:

• Cystatin C is a protease inhibitor meeting criteria for glomerular filtration rate (GFR) assessment.
• Serum creatinine is the current standard for GFR, but cystatin C shows superior predictive ability.
• Reluctance to adopt cystatin C is linked to higher reagent costs.

Purpose of the Study:

• To highlight the advantages of cystatin C over serum creatinine in assessing kidney function.
• To emphasize cystatin C's proven ability to predict adverse outcomes in chronic kidney disease (CKD).
• To support the integration of cystatin C into clinical practice for improved CKD management.

Main Methods:

• Measurement of cystatin C using automated, standardized immunoassays.
• Comparison of cystatin C and serum creatinine in predicting risks of kidney failure, cardiovascular events, and mortality.
• Review of national and international guidelines recommending cystatin C use.

Main Results:

• Cystatin C demonstrates superior predictive ability for adverse outcomes compared to creatinine in CKD patients.
• Strong evidence supports cystatin C's role in risk stratification for individuals with reduced GFR.
• Guidelines now recommend cystatin C for risk stratification in mild to moderate CKD without albuminuria.

Conclusions:

• Cystatin C offers a more accurate assessment of kidney function and patient risk than serum creatinine.
• Recommended use of cystatin C in guidelines facilitates better-targeted CKD management.
• Laboratories can leverage cystatin C measurement to optimize care for CKD patients.