Which statement about CKD stages is correct?

• A. Stage 3 CKD includes eGFR 45–59 (3a) or 30–44 (3b)
• B. Stage 5 CKD is eGFR <15 mL/min
• C. Stage 1 CKD is eGFR ≥90 with evidence of kidney damage
• D. Stage 2 CKD is eGFR 60–89

Answer: (A)

Understanding CKD stages hinges on two things: the estimated GFR range and, for the early stages, evidence of kidney damage. Stage 3 CKD is defined by a moderately reduced GFR, specifically 30–59 mL/min/1.73 m2, and it’s subdivided into 3a (45–59) and 3b (30–44). So the statement that Stage 3 CKD includes eGFR 45–59 (3a) or 30–44 (3b) is precisely aligned with how the stages are split and described, making it the best match.

Some other options are incomplete or require qualifiers that aren’t stated, which is why they’re not as accurate in this framing. For example, Stage 2 requires evidence of kidney damage in addition to the mildly reduced GFR (60–89), not just the GFR range alone. Stage 5 is defined as eGFR <15 mL/min and is typically described as stage 5 CKD or kidney failure, sometimes with dialysis status included. Stage 1 CKD is defined as normal or high GFR (≥90) with evidence of kidney damage, which is correct but depends on the presence of damage. The definition of Stage 3 given here is the clearest, most complete statement among the options.