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Evaluation of kidney function

Summary of normal urine specimen
1. alarming signs
  1. Red cell casts predominate in acute glomerulonephritis
  2. White cell casts predominate in tubulointerstitial disease
  3. Broad, waxy casts represent complete disintegration of embedded components, suggesting sluggish flow
    1. renal failure casts
  4. Calcium deficiency
    1. renal failure stage of chronic renal disease
  5. low creatinine clearance
    1. low GFR
  6. Hyperphosphatemia, hyperuricemia and acidosis
    1. do not develop until there is 70-80% loss of functional capacity
serum urea/creatinine ratio is normally about 15
Laboratory findings in specific syndromes
1. Nephrotic Syndrome
  1. proteinuria > 3 g/day
  2. hypoproteinemia and consequent edema
  3. hyperlipidemia
2. Nephritic Syndrome
  1. hematuria, proteinuria ( < 2 g/day)
  2. red cell casts
3. Tubulointerstitial Disease
  1. cloudy urine from high WBC
  2. white cell casts
  3. proteinuria ( < 1 g/day)
4. Acute Renal Failure
  1. sudden oliguria
  2. broad waxy casts (renal failure casts)
  3. urine sodium concentration > 40 mEq/L
Blood test
1. Blood urea nitrogen (BUN) test
  1. a rise in BUN indicates obstruction of urinary tract
Calculations
1. GFR = Cinulin = UV/P (inulin) ml/min
2. ERPF = CPAH = UPAHV/PPAH ml/min
3. Filtration fraction = GFR/ERPF
4. Filtered load for substance x = GFR . Px mg/min
5. Excretion rate for substance x= Ux (mg/ml) . V (ml/min) = mg/min
6. Secretion Rate= ER (mg/min) – FL (mg/min) = mg/min

Evaluation of kidney function

	Created by Zulhilmi Zainal over 10 years ago