Relationship Between the Reaction and Phosphate Concentration of Urine Specimens Collected Over Short Periods.

Abstract

Charts and tables showing relationships between the urinary reaction and phosphate concentration in short period experiments on subjects taking normal diets and eating a standard meal were prepared. The experimental technique has been described elsewhere. 1 The Bell-Doisy method was used in determining the phosphate concentration. 2 When equal reactions were found on 2 specimens of urine obtained at about the same time the actual pH values were usually fairly low, but there was a second, smaller group in which they were more alkaline. The reactions of relatively few specimens fell between pH values of 6.0 and 7.0. The authors believe that the former, larger group, probably represents a true physiological constancy of the reaction, while the smaller one where the reaction is more alkaline they think frequently contains instances in which those changes in the reaction of urine which take place after a specimen has been voided 3 have taken place under approximately constant conditions, and have produced a constancy of reaction which may have little physiological significance. The phosphate concentration was much higher in the more acid than in the more alkaline group.

Further study of the material brought out the following points: 1, when the reactions of 2 specimens of urine obtained from the same patient differed by 0.2 pH or less the average of the means of the phosphate concentration in the urine was about 20% higher than in the whole series; 2, when the reactions of 2 specimens differed by more than 2.0 pH the average of the means was 50% lower than in the series considered as a whole; 3, when the mean phosphate concentration was high very few specimens showed differences in reaction which were greater than 0.2 pH; 4, when the mean phosphate concentration was low about half of the specimens, even from patients with achlorhydria, showed differences in reaction greater than 0.2 pH; 5, the average mean pH was lower when the phosphate concentration was low than when it was high; 6, in many individual experiments there was little or no correlation between changes in reaction and in phosphate concentration; 7, the average phosphate concentration was higher in achlorhydria, possibly due to the small hourly volume of urine excreted, than it was in a short control series.