[Skip to Content]
[Skip to Content Landing]
November 13, 1991

Removing the pH From Physician Phrases

Author Affiliations

University of Florida College of Medicine Gainesville

University of Florida College of Medicine Gainesville

JAMA. 1991;266(18):2559. doi:10.1001/jama.1991.03470180059021

This article is only available in the PDF format. Download the PDF to view the article, as well as its associated figures and tables.


To the Editor.  —I was helping a group of medical students work through a complex acid-base problem last week. I recognized again how difficult it is for a novice to understand a complex physiological abnormality when the perturbed variable (H+ concentration) is expressed as the log of the reciprocal of the concentration: pH = log(1/[H+]), or the negative log of the concentration.In the days of Arrhenius, Severing-haus, and Henderson-Hasselbalch, concentrations expressed in nanomoles presented some difficulty for calculations. This is no longer true. In the 1990s, it is just as easy to consider hydrogen-ion concentration as 20, 40, or 60 nmol/L as it is to consider potassium as 3, 4, or 5 mmol/L.Using pH once served a useful purpose, like the horse and buggy, logarithms, and the slide rule. In the 1990s, pH no longer serves a useful purpose in clinical medicine. The concept of pH only adds confusion