In arterial blood gas interpretation (ABG), bicarbonate (HCO3) is a variable parameter highly influenced by the changes in the concentration of carbon–dioxide (pCO2). This is solved by measuring Standard bicarbonate. The deviation between these two values denotes the respiratory influence. This concept was applied in a previous research study for the development of a novel four quadrant graphical method for ABG interpretation. Their ratio was also applied for an equation inter–relating the total changes in pH to the changes in both the respiratory and non–respiratory component affecting the pH. A minor problem with the ratio {(HCO3– Standard HCO3) /carbonic acid} is that as the pCO2 increases, this ratio also increases but afterwards the curve flattens and may not clearly differentiate the different higher levels of pCO2 values. The aim of the current research study is to apply a modified bicarbonate/ Standard bicarbonate ratio in various acid base disturbances.