Evaluation and Management of Proteinuria and Hematuria

Introduction to Referral Guidelines

The American Urological Association and the Society of Urologic Nurses and Associates recommend that patients with proteinuria, dysmorphic RBCs, cellular casts, or renal insufficiency should be referred to a nephrologist, but this does not preclude the need for risk-based urologic evaluation to identify coexistent urologic pathology 1, 2
The Canadian Society of Nephrology recommends nephrology referral for persistent proteinuria >1 g/day because at this level, renal biopsy may be indicated and immunosuppressive medications may need consideration 3

Refer to nephrology when significant proteinuria is present, defined as total protein excretion >1 g/24 hours, as this threshold may warrant renal biopsy and immunosuppressive therapy 3, 4
Dysmorphic RBCs or red cell casts are indicative of glomerular bleeding and indicate medical renal disease, prompting nephrology referral 4, 5, 6
Elevated serum creatinine suggests renal parenchymal involvement and is an indication for nephrology referral 4, 6

Risk factors for genitourinary malignancy, such as age >40 years, smoking history, or occupational exposure to chemicals/dyes, warrant urology referral for risk-based evaluation 4, 6
Persistent microscopic hematuria after excluding benign causes and confirming on repeat urinalysis is an indication for urology referral 1, 2

When both proteinuria and hematuria are present, first assess for medical renal disease markers, including quantification of proteinuria and examination of urine sediment for dysmorphic RBCs and cellular casts 1, 2, 4, 5
If medical renal disease is suspected, refer to nephrology immediately and still perform urologic risk stratification 1, 2, 3

Do not assume a single etiology, as the presence of proteinuria does not exclude urologic malignancy, and hematuria does not exclude glomerular disease, and both evaluations must proceed in parallel when indicated 1, 2
Do not delay urologic evaluation in patients on anticoagulation, as receipt of antiplatelet or anticoagulant therapy is not a satisfactory explanation for hematuria 8
Do not perform renal biopsy for low-level proteinuria, as at proteinuria levels of 0.3 g/day without other concerning features, biopsy is not indicated and conservative management with ACE inhibitors/ARBs is appropriate 7