The Non-respiratory hydrogen ion concentration was suggested as one of the measure of metabolic acid-base disorders even before many decades but clinically not applied. Recently a simple formulae was derived using standard bicarbonate for its practical application. The Non-respiratory hydrogen ion concentration is found to be inter-related in various acid-base balance theory. The three commonly used approaches for arterial blood gas interpretation are physiological, Base excess and physicochemical approach. The respiratory acid base disorders are due to the alterations in the values of pCO2 which is common in all the approaches. But for metabolic acid base disorders different parameters are used in different approaches. The physiological approach uses Bicarbonate, Base excess approach utilizes Standard base excess and in physicochemical approach Stewarts's parameters like strong ion difference and the total concentration of dissociated non-volatile weak acids are applied. The aim of the current study is to derive an applied equation interrelating Stewart's theory parameters and the non-respiratory hydrogen ion concentration and its practical application in arterial blood gas interpretation.