Lab

Urine Microalbumin

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Urine Microalbumin, Microalbuminuria, Macroalbuminuria, Urine Microalbumin to Creatinine Ratio, Urine Albumin to Creatinine Ratio

  • Indications
  1. Diabetes Mellitus
  2. Hypertension
    1. Questionable efficacy as prognostic factor in Hypertension (contrast with Diabetes Mellitus)
  • Protocol
  1. Nephropathy diagnosis needs 2 of 3 samples positive
  2. Typically performed as a Urine Albumin to Creatinine Ratio (random spot urine collection)
  3. Consider postural Proteinuria (especially in adolescents)
    1. Obtain overnight timed urine collection
  1. Normal (or mildly increased)
    1. 24h Collection: <30 mg/day
    2. Timed Collection: <20 mcg/min
    3. Urine Albumin to Creatinine Ratio (Spot Collection): <30 mcg/mg Creatinine
  2. Microalbuminuria (moderately increased)
    1. 24h Collection: 30-300 mg/day
    2. Timed Collection: 20-200 mcg/min
    3. Urine Albumin to Creatinine Ratio (Spot Collection): 30-300 mcg/mg Creatinine
  3. Macroalbuminuria (severely increased)
    1. 24h CollecSpot Collectiontion: >300 mg/day
    2. Timed Collection: >200 mcg/min
    3. Urine Albumin to Creatinine Ratio (Spot Collection): >300 mcg/mg Creatinine
  • Interpretation
  • Urine Albumin to Creatinine Ratio
  1. Preferred over Urine Protein to Creatinine Ratio
    1. Higher Test Sensitivity (esp. at lower albumin levels) than Urine Protein to Urine Creatinine Ratio
    2. Widespread standardization across lab assays and countries
  2. Normal Ratio (in general <30 mg/g is normal)
    1. Men: < 0.017 (or 17 mg albumin to 1 gram Creatinine)
    2. Women: <0.025 (or 25 mg albumin to 1 gram Creatinine)
  3. Microalbuminuria (moderately increased): 30-300 mg albumin/g Creatinine
  4. Macroalbuminuria (severely increased): >300 mg albumin/g Creatinine
  5. False Positive causes
    1. Menstrual Bleeding
    2. Urinary Tract Infection
    3. Exercise