nephrology urinalysis lecture 2 10

• related: Nephrology

• best collected first morning void (most concentrated and acidic)

UA components

• specific gravity: how concentrated urine is
  • water: 1.000
  • concentrated urine >1.02
  • very concentrated >1.04
• Heme
  • • in hemolysis, rhabdo from myoglobin, rbc from hematuria
• Protein
  • small amount of urine protein can be from tubule <3g/day

  • 3 g/day is nephrotic proteinuria, suggest glomerular disorder

• RBC/WBC
  • 
  • 
    • rbc cast with biconcave shape
    • leaking blood from glomerulus and makes casts in tubule
    • seen in glomerulonephritis and vasculitis but not in lower urinary tract (beyond kidney)
  • 
    • WBC casts, bigger than RBC
    • seen in pyelo but not cystitis
    • AIN: PPI, abx. Sterile pyuria, fever, eosinophilia, rash
• urine eosinophils: not helpful
• Hyaline cast
  • uromodulin protein, normal
  • 
• Renal tubular epithelial cells
  • ATN
• Granular casts
  • ATN
  • damage to tubular cells
  • 
  • 
    • break off, slough, form cast
• Oval fat bodies: nephrotic syndrome
• Calcium oxalate crystals: acidic urine
  • 
  • ingestions: ethylene glycol
  • can be normal
• Urate crystals
  • 
• Triple phosphate
  • 
  • struvite stones
• Yeasts

Automated UA

• iQ200 and Cobas

Pre-renal Failure

• prior to glomerulus
• volume depletion
• high Bun/Cr
• concentrated urine, hyaline casts

Intrinsic

• Glomerular
  • proteinuria
  • hematuria, RBC casts
• Tubular

ATN

• Intrinsic
• Interstium or tubule
• UA: at least 1 granular cast, at least one renal tubular epithelial cells

Interstitial nephritis

• interstial nephritis
• allergic issues
• eosinophiluria not diagnostic
• pyuria not helpful

Postrenal

• obstruction

• Chronic renal failure

  • Hx of HTN, serum Cr, proteinuria, small kidneys on US

• UA only picks up albumin. UPC helpful to pick up myeloma and amyloid

Examples