How to manage urinalysis results showing proteinuria and hematuria?

Management of Urinalysis with Proteinuria and Hematuria

When urinalysis shows both proteinuria and hematuria, a systematic evaluation is required to determine if the source is glomerular or non-glomerular, with nephrology referral indicated for significant proteinuria (>500 mg/24 hours) or evidence of glomerular bleeding.

Initial Assessment

• First, exclude benign causes of hematuria including menstruation, vigorous exercise, sexual activity, viral illness, trauma, and infection 1
• Obtain a 24-hour urine collection to quantitate proteinuria when dipstick shows ≥1+ protein 1
• Examine urinary sediment for dysmorphic red blood cells and red cell casts, which suggest glomerular origin 1
• Measure serum creatinine to assess renal function 1, 2

Diagnostic Algorithm

Step 1: Determine if glomerular or non-glomerular source

• Glomerular source likely if:

  • Significant proteinuria (>500 mg/24 hours) 1
  • Dysmorphic RBCs (>80% dysmorphic RBCs suggest glomerular origin) 1
  • Red cell casts (pathognomonic for glomerular bleeding) 1
  • Elevated serum creatinine 1

• Non-glomerular (urologic) source likely if:

  • Normal-shaped RBCs (>80% normal RBCs suggest lower urinary tract bleeding) 1
  • Minimal proteinuria (<500 mg/24 hours) 1
  • Normal serum creatinine 1

Step 2: Management based on source determination

For Glomerular Source:

• Refer to nephrology if:

  • Proteinuria >1,000 mg/24 hours (mandatory referral) 1
  • Proteinuria >500 mg/24 hours that is persistent or increasing 1
  • Red cell casts or predominantly dysmorphic RBCs 1
  • Elevated serum creatinine 1

• Nephrology evaluation may include:

  • Evaluation for systemic diseases (lupus, vasculitis, infections) 1
  • Consideration of renal biopsy 1, 3

For Non-Glomerular (Urologic) Source:

• Complete urologic evaluation including:

  • History and physical examination 1, 2
  • Radiologic imaging of upper urinary tract 1, 2
  • Cystoscopic examination of urinary bladder 1, 2

• Refer to urology if:

  • Age >40 years 1
  • Smoking history 1
  • History of gross hematuria 1
  • Occupational exposure to chemicals or dyes 1
  • Previous urologic disorder 1
  • Irritative voiding symptoms 1
  • Recurrent urinary tract infections 1

Follow-up Recommendations

• For patients with persistent hematuria after negative initial evaluation:

  • Repeat urinalysis at 6,12,24, and 36 months 2
  • Monitor blood pressure 2
  • Consider nephrology referral if hematuria persists with development of hypertension, proteinuria, or evidence of glomerular bleeding 2

• For patients with isolated hematuria (no proteinuria or other abnormalities):

  • Follow for development of hypertension, renal insufficiency, or proteinuria 1

Important Caveats

• High specific gravity (≥1.020) and hematuria together can lead to false-positive proteinuria readings on dipstick 4
• Do not assume hematuria is due to anticoagulation therapy without proper evaluation 2
• Patients with microscopic hematuria, negative urologic evaluation, and no evidence of glomerular bleeding have low risk for progressive renal disease but should still be monitored 1
• Avoid routine screening for proteinuria in the general population; reserve for high-risk patients (diabetes, hypertension) 5
• In women, obtain a catheterized specimen if clean-catch cannot be reliably obtained due to vaginal contamination 1