What are the stages of renal failure based on glomerular filtration rate (GFR)?

Stages of Renal Failure Based on GFR

Chronic kidney disease is classified into five stages based on glomerular filtration rate (GFR), with Stage 1 starting at GFR ≥90 mL/min/1.73 m² (requiring evidence of kidney damage) and progressing to Stage 5 at GFR <15 mL/min/1.73 m² or dialysis requirement, representing kidney failure. 1, 2

The Five Stages of CKD

Stage 1: GFR ≥90 mL/min/1.73 m²

• Normal or increased kidney function with evidence of kidney damage (such as albuminuria, proteinuria, or structural abnormalities on imaging) 1, 2
• GFR alone is insufficient for diagnosis at this level—you must document kidney damage markers 1
• Clinical focus: diagnose and treat underlying conditions, slow progression, reduce cardiovascular disease risk 2

Stage 2: GFR 60-89 mL/min/1.73 m²

• Mildly decreased kidney function with evidence of kidney damage 1, 2
• Like Stage 1, requires documented evidence of kidney damage for CKD diagnosis 1
• Clinical focus: estimate disease progression rate 2

Stage 3: GFR 30-59 mL/min/1.73 m²

• Moderately decreased kidney function that can be diagnosed based on GFR alone without requiring additional evidence of damage 1
• Subdivided into two categories based on significantly different risk profiles: 1, 2
  • Stage 3a: GFR 45-59 mL/min/1.73 m² (slightly to moderately decreased) 3, 1, 2
  • Stage 3b: GFR 30-44 mL/min/1.73 m² (moderately decreased) 3, 1, 2
• Risk of complications increases significantly below GFR 60 mL/min/1.73 m² 1, 2
• Clinical focus: evaluate and treat complications, estimate progression rate 1, 2

Stage 4: GFR 15-29 mL/min/1.73 m²

• Severely decreased kidney function 1, 2
• Hypertension prevalence approaches 80% at this stage 1
• Multiple complications become substantially more likely when GFR falls below 30 mL/min/1.73 m² 1
• Nephrologist referral is mandatory for consultation and co-management 2
• Clinical focus: intensive management of complications and preparation for kidney replacement therapy 1, 2

Stage 5: GFR <15 mL/min/1.73 m² or Dialysis

• Kidney failure representing loss of more than 85% of kidney function 4, 5
• Also called "end-stage renal failure" in administrative contexts, though this terminology should be avoided in clinical documentation 4
• Clinical focus: kidney replacement therapy (dialysis or transplantation) if uremic symptoms develop 1, 2

Critical Diagnostic Requirements

All abnormalities must persist for at least 3 months to distinguish chronic from acute kidney disease. 1, 2 This 3-month threshold is mandatory for CKD diagnosis and differentiates it from acute kidney injury. 3

Complete Classification System

Use the CGA classification system (Cause, GFR category, Albuminuria category)—not GFR alone—for complete risk stratification. 1, 2 The combination of GFR and albuminuria provides superior risk stratification for disease progression and outcomes compared to GFR alone. 1

Albuminuria Categories to Include:

• A1: Normal to mildly increased albuminuria (<30 mg/g) 1
• A2: Moderately increased albuminuria (30-300 mg/g, previously called "microalbuminuria") 3, 1
• A3: Severely increased albuminuria (>300 mg/g) 3, 1

An albuminuria level of 30 mg/g represents more than 3 times the normal value and independently predicts increased risk for CKD complications, cardiovascular mortality, and progression to kidney failure. 1

GFR Estimation Method

Use the CKD-EPI equation for reporting estimated GFR in adults from serum creatinine calibrated to isotope-dilution mass spectrometry reference method. 1, 2 The CKD-EPI equation demonstrates less bias than the MDRD equation, especially at GFR ≥60 mL/min/1.73 m², with improved precision and greater accuracy. 1

Common Pitfalls to Avoid

• Never diagnose Stages 1-2 CKD based on GFR alone—you must document evidence of kidney damage such as albuminuria or structural abnormalities 1, 2
• Do not use serum creatinine alone—always calculate estimated GFR using prediction equations that account for age, sex, race, and body size 3, 1
• Avoid incomplete staging—classify using the complete CGA system (Cause, GFR category, Albuminuria category), not GFR alone 1
• Do not dismiss age-related GFR decline as "normal aging"—decreased GFR in elderly patients remains an independent predictor of adverse outcomes 2
• Avoid using "end-stage renal disease" (ESRD) or "end-stage renal failure" (ESRF) in clinical documentation—use "kidney failure" or "CKD Stage 5" instead, as these terms are poorly defined and carry stigma 4