CKD stage 1 is defined by evidence of kidney damage with an eGFR at least what value?

• A. eGFR 60-89 mL/min/1.73 m2 with evidence of kidney damage
• B. eGFR ≥90 mL/min/1.73 m2 with normal findings
• C. eGFR ≥90 mL/min/1.73 m2 with evidence of kidney damage
• D. eGFR 30-59 mL/min/1.73 m2

Answer: (C)

CKD staging uses both how well the kidneys are filtering (eGFR) and whether there is evidence of kidney damage. Stage one means there is kidney damage present even though filtration is still normal or high. That requires an eGFR of 90 mL/min/1.73 m2 or greater, plus some sign of kidney damage such as albuminuria, abnormal imaging, or other markers of kidney disease. So the correct pattern is eGFR ≥90 with evidence of kidney damage because you have damage without a reduced filtration rate. If there’s no evidence of damage, a normal or high eGFR isn’t CKD. If the eGFR is lower (60-89 or below 60), that points to later stages of CKD, even if damage is present.