Diagnostics

1. Confirm nephrotic-range proteinuria.

2. Assess for potential concomitant and underlying conditions.

3. Assess for nephrotic syndrome complications.

4. Consider kidney biopsy to determine renal pathology.

Confirmation of nephrotic-range proteinuria

• Qualitative assessment by urine dipstick (commonly used for screening)

  • Usually shows ≥ 3+ proteins

  • Hematuria may indicate concomitant glomerulonephritis.

• Quantitative assessment of urine protein excretion

  • 24-hour urine protein (test of choice): > 3.5 g/24 hours

  • Spot urine protein/creatinine ratio: > 3.5 g/g

Urine sediment microscopy

• Nephrotic sediment

  • Lipiduria, fatty casts with Maltese cross appearance under polarized light

  • Renal tubular epithelial cell casts

• Hematuria with acanthocytes and/or RBC casts may indicate concomitant glomerulonephriti

• CBC: ↑ Hb/Hct may indicate hemoconcentration

• BMP: ↑ Cr and/or ↑ BUN may be seen; ↓ Na is commonly seen.

• Serum protein: ↓ total protein, ↓ albumin (< 3 g/dL)

• Coagulation factors: ↓ ATIII, ↓ protein S, ↓ plasminogen ; ↑ fibrinogen, ↑ D-dimer

• Lipid profile: Hyperlipidemia (↑ LDL, ↑ triglycerides) may be present.

• Vitamin D levels: ↓ 25-OH Vit-D

• Inflammatory markers: ↑ ESR, ↑ CRP may suggest underlying infection, inflammatory condition, or vasculitis.

Renal ultrasound: to assess kidney size and shape and rule out obstruction

to confirm the diagnosis when the etiology of nephrotic syndrome is unclear and/or to guide management

• Often required in adult patients to guide management.

• Sometimes deferred when a likely cause of nephrotic symptoms is evident

• Consult nephrology to determine the necessity and timing of biopsy

See pathology