The 5 stages  of  Chronic Kidney Disease: The stages are determined by your Glomerular Filtration Rate (GFR), which measures how well your kidneys filter blood. [ 1 , 2 ] Stage 1:   Kidney damage with normal or high GFR (90+ mL/min). Kidneys still function, but there are signs of damage like protein in the urine. [ 1 , 2 ] Stage 2:   Mild decrease in GFR (60–89 mL/min). Slight decline in function, often with few noticeable symptoms. [ 1 , 2 ] Stage 3:  Moderate to severe decrease. Stage 3a: GFR 45–59 mL/min. Stage 3b: GFR 30–44 mL/min. *Note: Users on Mayo Clinic Connect agree that Stage 3 is when symptoms like fatigue and swelling typically start becoming more noticeable. [ 1 , 2 , 3 , 4 , 5 ] Stage 4:   Severe decrease in GFR (15–29 mL/min). Waste buildup causes more apparent symptoms like nausea, fatigue, and bone issues. [ 1 , 2 , 3 , 4 , 5 ] Stage 5 (ESRD):   Kidney failure (GFR less than 15 mL/min). Kidneys stop working adequately to sustai...