GFR 25 mL/min/1.73 m² Corresponds to Stage G3b Chronic Kidney Disease
A glomerular filtration rate of 25 mL/min/1.73 m² classifies the patient as having Stage G3b chronic kidney disease, defined as moderately to severely decreased kidney function (eGFR 30-44 mL/min/1.73 m²). 1
KDIGO CKD Staging System
The Kidney Disease: Improving Global Outcomes (KDIGO) classification stratifies chronic kidney disease by eGFR into the following stages: 1
- Stage G1: ≥90 mL/min/1.73 m²
- Stage G2: 60-89 mL/min/1.73 m²
- Stage G3a: 45-59 mL/min/1.73 m²
- Stage G3b: 30-44 mL/min/1.73 m² (← GFR 25 falls here)
- Stage G4: 15-29 mL/min/1.73 m²
- Stage G5: <15 mL/min/1.73 m² (kidney failure)
Clinical Significance of Stage G3b
Stage G3b represents loss of approximately two-thirds of normal kidney function and carries substantially elevated risks compared to earlier stages. 1 Specifically, this stage is associated with: 1
- Markedly increased cardiovascular disease risk
- Accelerated CKD progression
- Increased mortality
Critical Diagnostic Requirement
A single eGFR measurement is insufficient for CKD diagnosis. 2, 1 Chronic kidney disease requires persistent abnormalities (eGFR <60 mL/min/1.73 m² and/or albuminuria ≥30 mg/g) documented for at least 3 months. 2, 1
Common Pitfall to Avoid
Do not underestimate the severity of Stage G3b disease simply because it is grouped under "Stage 3." 1 Despite sharing the "Stage 3" designation with G3a (eGFR 45-59), Stage G3b carries significantly higher risks and warrants more aggressive monitoring, nephrology involvement, and screening for CKD complications. 1
The case examples provided in the evidence consistently describe patients with eGFR 25 mL/min/1.73 m² as having "CKD stage 4" 3, which appears to be an error in those older documents, as the correct KDIGO classification places this value in Stage G3b. 1