To overcome this limitation, Siggaard-Andersen introduced the base excess (BE), i.e. the "excess" (either positive or negative) of the actual BB as compared to the Normal BB (NBB). Base excess (BE) was introduced by Siggaard-Andersen in 1960 as an answer to the forty-year-long quest for a reliable, stand-alone marker of metabolic acidosis/alkalosis, independent from co-existing respiratory derangements, and able to quantify the severity of the disorder [[1]]. Consequently, BE is the amount of acid/base (mmol/L) that must be added to the blood sample to reach pH of 7.40 in standardized conditions (PCO SB 2 sb 40 mmHg, 37 °C) [[6]]. The patient could therefore have normal acid-base parameters (pH 7.40, pCO SB 2 sb 40 mmHg, HCO SB 3 sb SP - sp 24 mmol/L) yielding a perfectly normal SBE of 0 mmol/L. Is the value of SBE in this context wrong?. [Extracted from the article]