BASIC STUDIES ON TITRATION-CURVE ANALYSIS OF URINE

Studies on Urinary Acidification I

Abstract

The previous method which measures urinary acid excretion has various disadvantages in its measurement. The auto-recording titrable apparatus, by which the titration curve and its differential curve were calculated, were used to the measurement of the level of urinary weak acids.
Using this apparatus, we investigated the influences of 1) temperature 2) hematuria 3) urinary protein and 4) bacteriuria on the urinary pH and the urinary level of weak acids.
The results were as follows:
1. Urine specimens, when they had been left at room temperature for only 2 days, showed marked changes in the urinary pH and the level of weak acids. The specimens frozen at -20°C for 30 days, however, did not produce any changes.
2. The hematuria, which was clinically recognized as a marked macroscopic hematuria, does not influence on the level of weak acids in specimens. The slight increase of urinary pH was shown in the same experiments. This, however, does not seem to bring any unfavorable results to clinical practice.
3. Urinary pH and the level of titrable acid were not influenced by the addition of albumin and γ-globulin to the speciments, although the urinary level of NH₄⁺ was slightly increased in a few samples.
4. Bacteriuria with either E. coli, Pseudomonas aeruginosa or Proteus mirabilis, produced some increase of urinary pH and the level of NH₄⁺, and some decrease of the level of urinary titrable acid. The most prominent changes were observed in the cases of bacteriuria with Proteus mirabilis even after incubation of urine for 5 hours. In cases of bacteriuria, therefore, careful interpretation of results is necessary in the measurement of urinary pH, the level of urinary titrable acid and NH₄⁺.