Urinary pH and the indwelling catheter

The pH of the urine within a blocked indwelling catheter was significantly higher than the pH of the first urine portion from the new catheter. This observation suggests that the urinary pH was changed in an alkaline direction within the indwelling catheter, probably due to the production of ammonia induced by urease from Proteus strains. This pH gradient could only be demonstrated under conditions where the circadian pH variations of the urine within the individual could be neglected.