When should a patient with chronic kidney disease be referred to a nephrologist (e.g., eGFR < 30 mL/min/1.73 m², rapid eGFR decline > 5 mL/min/1.73 m²/yr, proteinuria ≥ 1 g/day, refractory hypertension despite ≥3 agents including ACE inhibitor/ARB, significant electrolyte or mineral‑bone disorders, persistent hematuria, progression despite optimal therapy, need for dialysis or transplant evaluation, pregnancy, or systemic disease affecting the kidneys)?

When to Refer to Nephrologist for CKD

Refer patients with CKD to nephrology when eGFR falls below 30 mL/min/1.73 m², when there is continuously increasing albuminuria with continuously decreasing eGFR, or when there is uncertainty about kidney disease etiology or difficult management issues. 1

Absolute Referral Criteria

eGFR-Based Thresholds

• eGFR <30 mL/min/1.73 m² (Stage G4-G5) is a mandatory referral threshold regardless of albuminuria status or other factors 1, 2, 3
• This threshold applies to all patients including those with diabetes, and represents the single most consistent recommendation across all major guidelines 1, 2, 3

Progressive Kidney Disease

• Rapid eGFR decline >5 mL/min/1.73 m² per year warrants nephrology consultation 2, 4
• Abrupt sustained eGFR decrease >20% after excluding reversible causes (volume depletion, medication effects, obstruction) requires specialist input 2
• Continuously increasing urinary albumin levels combined with continuously decreasing eGFR should trigger referral even if eGFR remains >30 mL/min/1.73 m² 1, 3

Proteinuria Thresholds

• Persistent proteinuria >1 g/day (ACR ≥60 mg/mmol or PCR ≥100 mg/mmol) requires nephrology referral 2
• Albuminuria ≥300 mg/g (A3 category) in combination with eGFR 30-44 mL/min/1.73 m² (Stage G3b) is an indication for referral 3
• Confirm persistent albuminuria with two of three specimens collected over 3-6 months due to >20% biological variability 1, 3

Prompt Referral Situations

Uncertain Etiology

• Absence of diabetic retinopathy in type 1 diabetes with kidney disease suggests non-diabetic kidney disease and requires prompt referral 3
• Active urinary sediment, gross hematuria with albuminuria, or rapidly increasing albuminuria warrant immediate consultation 3
• Urinary red cell casts or RBC >20 per high power field sustained and not readily explained require specialist evaluation 2
• Duration of type 1 diabetes <10 years with significant kidney disease is atypical and needs nephrology assessment 3

Difficult Management Issues

• Hypertension refractory to treatment with 4 or more antihypertensive agents requires nephrology referral 2
• Persistent abnormalities of serum potassium or other electrolyte disturbances need specialist input 2
• Secondary hyperparathyroidism, metabolic bone disease, or persistent metabolic acidosis warrant consultation 3
• Anemia requiring evaluation in the context of CKD should prompt referral 3

Special Populations

• Recurrent or extensive nephrolithiasis requires nephrology evaluation 2
• Hereditary kidney disease should be referred to nephrology 2
• Pregnancy in patients with CKD warrants specialist co-management 2

Risk-Stratified Referral Based on Combined eGFR and Albuminuria

Stage G3a (eGFR 45-59 mL/min/1.73 m²)

• Refer if albuminuria ≥300 mg/g (A3 category) 3
• Monitor twice yearly if albuminuria 30-299 mg/g (A2 category) without referral 3

Stage G3b (eGFR 30-44 mL/min/1.73 m²)

• Refer with any level of albuminuria 3
• Monitor three times yearly if not yet referred 3

Stages G4-G5 (eGFR <30 mL/min/1.73 m²)

• Mandatory referral at all albuminuria levels 1, 3
• Monitor four times yearly for Stage G4 3

Important Caveats and Common Pitfalls

Do Not Refer

• Stage G1-G2 CKD with normal albuminuria (<30 mg/g) and stable eGFR does not warrant nephrology referral 4
• Patients with eGFR <30 mL/min/1.73 m² may not require referral if GFR is stable, diagnosis is clear, and very advanced age or comorbidity indicates short life expectancy 2

Do Not Discontinue RAAS Blockade

• Small creatinine elevations up to 30% from baseline with ACE inhibitors or ARBs are expected and should not trigger referral or medication discontinuation in the absence of volume depletion 1, 3

Recognize Non-Diabetic Kidney Disease

• CKD may be present at diagnosis of type 2 diabetes, so diabetes duration alone is unreliable 3
• Retinopathy is only moderately sensitive and specific for diabetic kidney disease in type 2 diabetes—its absence does not exclude diabetic nephropathy but should raise suspicion for alternative diagnoses 3
• Reduced eGFR without albuminuria is increasingly common in type 2 diabetes and still represents diabetic kidney disease 3

Avoid Late Referral

• Late referral (less than 1 year before start of renal replacement therapy) is associated with worse outcomes 2
• Earlier referral when Stage 4 CKD develops (eGFR <30) reduces cost, improves quality of care, and delays dialysis 3

Address Cardiovascular Risk

• The vast majority of early-stage CKD patients die primarily from cardiovascular causes rather than progressing to end-stage kidney disease 4, 5
• Focus on blood pressure control (target <140/90 mm Hg, or <130/80 mm Hg with diabetes/CVD), lipid management, and lifestyle modifications in low-risk CKD 4

Multidisciplinary Care Approach

• Patients with progressive CKD at high risk of ESRD with eGFR <30 mL/min/1.73 m² benefit from a multidisciplinary approach including dietary counseling, education about renal replacement therapy options, transplant options, vascular access surgery, and psychological support 2
• Primary care providers should not delay patient education about progressive kidney disease and treatment benefits while awaiting nephrology consultation 3