dipstick urinanalysis (pH)

Last reviewed 01/2018

pH:

• The pH of normal urine is generally in the range 4.6 - 8, a typical average being around 6.0
  
  
  • much of the variation is due to diet
    • for example, high protein diets result in more acidic urine, but vegetarian diets generally result in more alkaline urine (both within the typical range 4.6 - 8)
      
      
  • alkaline urine is associated with infection with urease-splitting organisms (e.g. Proteus, Klebsiella)
    • urea splitting bacteria are related to the formation of struvite-apatite
      • struvite stones are potentiated by bacterial infection that hydrolyzes urea to ammonium and raises urine pH to neutral or alkaline values
      • upper urinary tract stones that involve the renal pelvis and extend into at least 2 calyces are classified as staghorn calculi
        • although all types of urinary stones can potentially form staghorn calculi, approximately 75% are composed of a struvite-carbonate-apatite matrix
          
          
  • urine pH generally reflects the blood pH but this is not the case in renal tubular acidosis (RTA)
    • type 1 RTA (distal) the urine is acidic but the blood alkaline
    • type 2 RTA (proximal) the urine is initially alkaline
      • however urine becomes more acidic as the disease progresses

Reference:

• Whitehead E. Urinarlyis Presentation. East Lancashire HC NHS Trust (2010)