eGFR (creatinine + cystatin C)

Estimated Glomerular Filtration Rate (eGFR, creatinine + cystatin C) is a more refined measure of kidney function that combines two blood markers—creatinine and cystatin C—along with age and sex. Because creatinine and cystatin C are influenced by different factors, using both together often provides a more accurate estimate of how well the kidneys are filtering waste, especially in people with unusual muscle mass or borderline results. eGFR is reported on the same scale (mL/min/1.73m²), and CKD stages use the same cutoffs (e.g., Stage 3 <60). As with the creatinine-only eGFR, values ≥90 are generally ideal, while sustained values below 60 indicate reduced kidney function and warrant medical follow-up.