Lab

Urine pH

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Urine pH, Urine Dipstick pH

  • See Also
  1. Urinalysis
  • Interpretation
  1. Normal pH: 4.5-8.0 (usually 5.5 to 6.5)
  • Background
  1. Urine pH reflects serum pH except with Renal Tubular Acidosis (RTA)
  2. In Renal Tubular Acidosis (RTA), Urine pH >5.5
    1. Urine cannot be acidified despite acid load
  • Causes
  • Increased Urine pH (Alkalotic urine)
  1. Stale sample with high ammonia content (Very high pH)
    1. Void testing if old sample
  2. Bacteriuria or Urinary Tract Infection
    1. Reflects urea splitting organisms (urease positive Bacteria such as Proteus species)
    2. Associated with Magnesium-ammonium phosphate crystals
  3. Urolithiasis
    1. Calcium Phosphate Calculi
    2. Struvite Calculi (infected stones, Magnesium-ammonium phosphate stones)
  4. Vegetarian Diet
  5. High citrate diet
  6. Renal Failure
  7. Renal Tubular Acidosis (Type 1)
  8. Drugs
    1. Antibiotics
    2. Bicarbonate (e.g. Excessive Antacid Use)
    3. Carbonic Anhydrase Inhibitor (e.g. Acetazolamide)
    4. Potassium Citrate
    5. Sodium Citrate
  • Causes
  • Decreased Urine pH (Acidic urine)
  1. Acidosis (Acidemia)
  2. Diabetic Ketoacidosis
  3. Starvation Ketosis
  4. Diarrhea
  5. Urolithiasis
    1. Uric Acid Calculi
    2. Cysteine Calculi
    3. Calcium Oxalate Calculi
  6. Acidic fruits (Cranberry)
  7. High Protein diet
  8. Drugs
    1. Ammonium chloride
    2. Methenamine
  • References
  1. Hitzeman (2022) Am Fam Physician 106(1): 27-35 [PubMed]
  2. Simerville (2005) Am Fam Physician 71(6): 1153-62 [PubMed]