GFR for stage 4 kidney damage with severe, low GFR?

• A. > 90 mL/min/1.73 M2
• B. 60-80 mL/min/1.73 M2
• C. 15-20 mL/min/1.73 M2
• D. 30-59 mL/min/1.73 M2

Answer: (C)

GFR-based CKD staging uses numerical ranges to show how well the kidneys filter. Stage 4 is a severe decrease in filtration, defined roughly as a GFR between 15 and 29 mL/min/1.73 m². The range 15–20 mL/min/1.73 m² falls within that 15–29 window, so it matches stage 4 and reflects a substantial loss of kidney function. Other ranges align with earlier stages: above 90 is normal or near-normal function; 60–89 indicates mild decrease (stage 2); and 30–59 corresponds to stage 3. Hence, the option describing GFR in the mid-teens up to the 20s best represents stage 4.