When to Refer to Nephrology
Patients should be referred to a nephrologist when they have an eGFR <30 mL/min/1.73 m² (CKD stage G4-G5), persistent significant albuminuria (>1 g/day), or rapid progression of kidney disease, as these conditions significantly increase mortality and morbidity risks. 1
Key Indications for Nephrology Referral
Kidney Function Criteria
- eGFR <30 mL/min/1.73 m² (CKD stages G4-G5) 1
- Rapid decline in kidney function (decrease in eGFR >20% after excluding reversible causes) 1
- Risk of kidney failure within 1 year of 10-20% or higher (using validated prediction tools) 1
Proteinuria/Albuminuria Criteria
- Persistent proteinuria >1 g/day (ACR ≥60 mg/mmol or PCR ≥100 mg/mmol) 1
- At this level, renal biopsy and immunosuppressive medications may be considered
Specific Clinical Presentations
- Urinary red cell casts or RBC >20 per high power field (sustained and unexplained) 1
- Hypertension refractory to treatment with 4+ antihypertensive agents 1
- Persistent electrolyte abnormalities (particularly potassium) 1
- Recurrent or extensive nephrolithiasis 1
- Hereditary kidney disease 1
- Suspected polycystic kidney disease 1
Diabetic Kidney Disease
- For diabetic patients: continuously increasing urinary albumin levels and/or continuously decreasing eGFR 1
- Uncertainty about etiology of kidney disease in diabetic patients 1
Timing of Referral
Early referral (>12 months before potential need for renal replacement therapy) is associated with:
- Reduced mortality even up to 5 years after initiation of renal replacement therapy 2
- Slower decline in renal function 2
- Better preparation for potential dialysis or transplantation 1
Special Considerations
Acute Kidney Injury (AKI)
- Not all AKI requires nephrology referral 1
- Primary care can manage AKI with:
- Treatment of precipitating causes (intercurrent illness, volume depletion)
- Temporary discontinuation of RAS blockade and NSAIDs
- Correction of obstruction
- Refer for AKI when:
- Abrupt sustained decrease in eGFR >20% after excluding reversible causes
- Features suggesting diagnosis other than prerenal azotemia or acute tubular necrosis 1
Elderly Patients
- Advanced age alone should not preclude referral
- Consider comorbidities, life expectancy, and patient preferences
- It may be reasonable not to refer some elderly patients with stable eGFR <30 mL/min/1.73 m² if the diagnosis is clear and life expectancy is limited 1
Stable CKD Stage 3
- Most patients with stage 3 CKD do not progress to end-stage renal disease
- Primary care intervention for cardiovascular risk reduction should be prioritized 1
- Consider nephrology referral for stage 3 CKD if:
- Difficult management issues
- Uncertainty about diagnosis
- Inability to meet blood pressure goals 1
Multidisciplinary Care
For patients with progressive CKD who are at high risk of ESRD with eGFR <30 mL/min/1.73 m², a multidisciplinary approach is beneficial and should include:
- Dietary counseling
- Education about renal replacement therapy options
- Transplant evaluation
- Vascular access planning
- Psychological and social support 1
Common Pitfalls to Avoid
Late referral - Referring patients <1 year before potential need for renal replacement therapy leads to poorer outcomes 1, 3
Over-referral - Not all patients with CKD need specialist care; this can strain nephrology resources 4
Under-referral - Missing opportunities for interventions that could slow progression or prepare for renal replacement therapy 5
Ignoring non-GFR indicators - Significant proteinuria or rapid GFR decline may warrant referral even with relatively preserved GFR 1, 6
Failure to recognize urgent situations - Some presentations require immediate nephrology evaluation (e.g., rapidly declining kidney function, severe electrolyte disturbances) 6
By following these evidence-based referral guidelines, primary care providers can ensure timely specialist involvement for patients who will benefit most, while appropriately managing less severe or stable kidney disease in the primary care setting.