Cystatin C is ready for clinical use.

Area of Science:

• Clinical Chemistry
• Nephrology
• Pharmacology

Background:

• Serum creatinine is the standard biomarker for estimating glomerular filtration rate (GFR).
• Creatinine-based estimated GFR (eGFR) equations have limitations, including the use of race coefficients.
• Accurate GFR estimation is crucial for medication dosing, especially for drugs with narrow therapeutic windows.

Purpose of the Study:

• To highlight clinical situations where cystatin C is a superior alternative GFR biomarker to creatinine.
• To address the controversy surrounding eGFR accuracy in medication prescribing.
• To emphasize the benefits of cystatin C in improving patient care through enhanced GFR estimation.

Main Methods:

• Review of studies comparing cystatin C and creatinine for GFR estimation.
• Analysis of medication dosing and monitoring strategies using cystatin C-based eGFR.
• Evaluation of the impact of cystatin C on achieving target drug levels.

Main Results:

• Cystatin C-based GFR equations are more accurate than creatinine-based equations across all age groups, particularly in acutely ill patients.
• Cystatin C improves the prediction of drug elimination and target levels for medications like vancomycin.
• Using cystatin C avoids the need for race coefficients, reducing imprecision in eGFR.
• Medication dosing guided by cystatin C leads to better achievement of therapeutic drug trough levels.

Conclusions:

• Cystatin C provides a more accurate GFR estimation, crucial for optimizing medication therapy.
• Widespread clinical availability of cystatin C testing is necessary for improved patient safety and drug efficacy.
• Implementing cystatin C can enhance the precision of prescribing medications with narrow therapeutic windows.