CKD Stage G2 GFR Range
The correct answer is B: 60 to 89 mL/min/1.73 m² defines CKD stage G2, which represents slightly decreased GFR with evidence of kidney damage. 1
GFR Classification for CKD Staging
The standardized CKD staging system classifies kidney function based on estimated glomerular filtration rate (eGFR) as follows:
- Stage G1: ≥90 mL/min/1.73 m² (normal or increased GFR with kidney damage) 1
- Stage G2: 60-89 mL/min/1.73 m² (slightly decreased GFR with kidney damage) 1
- Stage G3a: 45-59 mL/min/1.73 m² (mild to moderate GFR decrease) 1
- Stage G3b: 30-44 mL/min/1.73 m² (moderate to severe GFR decrease) 1
- Stage G4: 15-29 mL/min/1.73 m² (severe GFR decrease) 1
- Stage G5: <15 mL/min/1.73 m² or dialysis (kidney failure) 1
Important Clarifications
For stages G1 and G2, the diagnosis of CKD requires evidence of kidney damage in addition to the GFR value. 1 Kidney damage is defined as:
Options C and D (30 mg/g and 30-300 mg/g) refer to albumin-to-creatinine ratio measurements, not GFR values, and therefore do not define CKD stages. 1 These values represent categories of albuminuria used in conjunction with GFR staging to provide a complete CKD classification.
Clinical Context
Stage G2 CKD represents early kidney disease where GFR is only mildly reduced but still above the threshold (60 mL/min/1.73 m²) that defines more advanced CKD. 1, 2 At this stage, patients typically require annual screening with UACR and serum creatinine for eGFR calculation 1, along with management of underlying conditions such as diabetes and hypertension to prevent progression 1.