Stage 1: Kidney damage with normal GFR (≥90 mL/min/1.73 m²) Stage 2: Mild decrease in GFR (60-89 mL/min/1.73 m²) Stage 3: Moderate decrease in GFR (30-59 mL/min/1.73 m²) Stage 4: Severe decrease in GFR (15-29 mL/min/1.73 m²) Stage 5: Kidney failure (GFR
