Chronic Kidney Disease: Egfr & Staging

Key points

• Serum creatinine alone may not accurately reflect renal function due to differences in muscle mass, ethnicity, age, and diet
• Eating red meat within 12 hours of the sample can transiently raise creatinine and affect the result
• eGFR is calculated from serum creatinine, age, sex and ethnicity
• CKD is staged by GFR (G1–G5): G1 > 90, G2 60–89, G3a 45–59, G3b 30–44, G4 15–29, G5 < 15 mL/min/1.73m²
• G1 and G2 only count as CKD if there is other evidence of kidney damage (e.g. proteinuria, haematuria, structural abnormality)
• CKD is also staged by albuminuria category (A1–A3) alongside the GFR category