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A. Functionalnavigator

  1. Urinalysis
    1. Dipstick: Hematuria, Erythrocytes (RBC), RBC Casts, Proteinuria
    2. Bactiuria, Leukocytes (WBC), WBC Casts
    3. Urine Output: oliguria, anuria, polyuria
    4. Urine Chemistry: electrolytes, protein (albumin, globulin), creatinine
  2. Blood
    1. Renal Function: BUN and Creatinine
    2. Electrolytes: including Ca, Mg, Phosphate
    3. Serum albumin (and globulin levels)
  3. Inflammation: complement levels, ESR, consider ANCA, anti-GBM Abs, ANA, etc.
  4. Calculation of Creatinine Clearance (CrCl)
    1. 24 hour urine creatinine collection required
    2. CrCl = {urine creat (mg/mL) x volume (mL)}/{plasma creat (mg/dL) x time (min)}
    3. Normal CrCl 125 mL/min/1.73m2 or ~80-100mL/min
  5. Estimation of Creatinine Clearance
    1. Men CrCl (mL/min) ~ (140-Age)x(weight in kg)/(72xserum creatinine)
    2. Women CrCl (mL/min) ~ equation above for men x 0.85
    3. Nuclear medicine imaging (renal scan) can be used to estimate GFR
  6. Estimation of Protein Losses [1]
    1. Obtain spot urine protein and creatinine
    2. Normal protein:creatinine ratio is 0.4 = Up/Uc
    3. Estimate 24 hour urine protein in gm = (estimated creatinine clearance x Up/Uc)/5
    4. Requires that urine protein and urine creatinine be in the same units
  7. Normal 24 hour Urine Collection Values
    1. Normal 24 hour urine creatinine 15-25 mg/kg
    2. Normal 24 hour calcium <200 mg/day
    3. Normal 24 hour citrate <320 mg/day
    4. Normal 24 hour cysteine <200 mg/day
    5. Normal 24 hour oxalate <44 mg/day
    6. Normal 24 hour uric acid <600 mg/day

B. Non-Invasive Radiography navigator

  1. Abdomen
    1. KUB Radiograph (Kidney, Ureter, Bladder); detects ~80% of renal stones
    2. Poor for evaluation of other problems
  2. Ultrasound: dilated pelvices, cysts, shadows of stones
  3. Computerized Tomography (CT)
    1. Good delineation of renal and other structures, shape
    2. Angiography with intravenous contrast dye
  4. Magentic Resonance (MR)
    1. Good delineation of structure, vascular involvement of tumors
    2. MR Angiography - does not require contrast dye
  5. Inflammatory Lesions
    1. Indium Labelled WBC (infection, inflammation) - usually preferred for abdominal studies
    2. Gallium Scan (infection, inflammation; high intestinal background)

C. Invasive Testingnavigator

  1. Vascular Angiography: IVP (intravenous pyelogram); very good for stones, obstruction
  2. Retrograde Pyelogram: Ureters
  3. VCUG: voiding cystourethrogram. Assess reflux nephropathy
  4. Bladder Assessment: Cystogram, cystoscopy
  5. Urethra: Urethrogram

D. Structure / Function Tests navigator

  1. Nuclear Medicine
    1. DMSA: Tubular secretion only (nephrogram); not filtered
    2. DTPA: Exclusively for evaluation of glomerular filtration
    3. May be used to assess for renal artery stenosis with captopril dosing
    4. This is called "captopril renogram"
  2. Magnetic Resonance Angiography
    1. Easy to assess renal vasculature
    2. No side effects on function from contrast dye
    3. Spiral CT angiography is "gold standard" for vessel assessment

E. Proteinuria Evaluation navigator

  1. Usually detected first by urine dipstick showing >1+ protein
  2. If urine dipstick shows >1+ protein, then further evaluation should be done
    1. Urinary microscopic examination
    2. 24 hour urine collection for total protein
  3. If 24 hour urine has >150mg of protein, then urine protein electrophoresis should be done
  4. Urinary protein electrophoresis (UPEP) will detect albumin versus other (smaller) molecules

References navigator

  1. Ginsberg JM, Chang BS, Matarese RA, Garella S. 1983. NEJM. 309:1543 abstract