When should a patient see a nephrologist (kidney specialist)?

When to Refer a Patient to a Nephrologist

Refer patients to nephrology when eGFR is <30 mL/min/1.73 m² or when there is progressive kidney disease with declining eGFR, significant proteinuria >1 g/day, or diagnostic uncertainty about the cause of kidney disease. 1

Mandatory Referral Criteria

Based on eGFR Thresholds

• Refer all patients with eGFR <30 mL/min/1.73 m² (Stage 4-5 CKD) to nephrology for evaluation and co-management 1, 2
• Exception: Stable eGFR <30 mL/min/1.73 m² in elderly patients with clear diagnosis and short life expectancy may not require formal referral, though specialist advice should still be sought 1

Based on Proteinuria/Albuminuria

• Refer patients with persistent proteinuria >1 g/day (ACR ≥60 mg/mmol or PCR ≥100 mg/mmol), as this level warrants consideration for kidney biopsy and potential immunosuppressive therapy 1, 2
• Refer patients with continuously increasing urinary albumin levels despite optimal treatment 1
• For diabetic patients specifically, refer when albuminuria is ≥300 mg/g creatinine with declining eGFR 1

Based on Disease Progression

• Refer patients with rapid eGFR decline >5 mL/min/1.73 m² per year 2
• Refer patients with abrupt sustained eGFR decrease >20% after excluding reversible causes (volume depletion, medication effects, obstruction) 1, 2
• Refer patients with continuously decreasing eGFR even if above 30 mL/min/1.73 m² 1

Urgent/Prompt Referral Situations

Diagnostic Uncertainty

• Immediately refer when etiology of kidney disease is unclear, particularly with: 1, 2
  • Absence of diabetic retinopathy in diabetic patients with kidney disease
  • Heavy proteinuria with active urine sediment
  • Urinary red cell casts or RBC >20 per high-power field sustained and unexplained
  • Rapidly progressive kidney disease
  • Suspected hereditary kidney disease (polycystic kidney disease, hereditary nephritis)

Acute Kidney Injury (AKI)

• Refer AKI cases with features beyond prerenal azotemia or acute tubular necrosis 1, 2
• AKI in primary care can often be managed locally if due to volume depletion, intercurrent illness, or medication effects, but sustained decline requires specialist input 1

Difficult Management Issues

• Refer patients with hypertension refractory to ≥4 antihypertensive agents 1, 2
• Refer patients with persistent electrolyte abnormalities (particularly hyperkalemia) 1, 2
• Refer patients with recurrent or extensive nephrolithiasis 1, 2
• Refer patients with CKD complications including anemia, secondary hyperparathyroidism, metabolic bone disease, or severe electrolyte disturbances 1

Planning for Renal Replacement Therapy

• Refer patients with progressive CKD when risk of kidney failure within 1 year is 10-20% or higher using validated risk prediction tools 1
• This allows timely planning for dialysis access, transplant evaluation, and patient education about treatment options 1, 2

Special Considerations for Diabetic Patients

• Refer diabetic patients with eGFR <30 mL/min/1.73 m² 1, 2
• Refer diabetic patients with continuously increasing albuminuria and/or continuously decreasing eGFR 1
• Consider earlier referral for diabetic patients without retinopathy who have kidney disease, as this suggests possible non-diabetic kidney disease 1, 2

Common Pitfalls to Avoid

• Do not delay referral until eGFR is <15 mL/min/1.73 m², as late referral (<1 year before dialysis) is associated with worse outcomes 2
• Do not discontinue ACE inhibitors or ARBs for mild creatinine increases <30% in the absence of volume depletion 1
• Do not assume all kidney disease in diabetic patients is diabetic kidney disease—absence of retinopathy, heavy proteinuria, or active sediment suggests alternative diagnosis requiring biopsy 1, 2
• Do not refer all Stage 3a CKD patients (eGFR 45-59 mL/min/1.73 m²) unless there is progression, significant proteinuria, or diagnostic uncertainty 1

When Nephrology Consultation May Not Be Necessary

• Stable eGFR 30-59 mL/min/1.73 m² (Stage 3 CKD) with clear diagnosis, controlled blood pressure, and minimal proteinuria can be managed in primary care with periodic monitoring 1
• Very elderly patients with stable, isolated eGFR <30 mL/min/1.73 m² and limited life expectancy may benefit from specialist advice rather than formal ongoing nephrology care 1