Lars Wiklund (1996) Carbon Dioxide Formation and Elimination in Man, Upsala Journal of Medical Sciences, 101:1, 35-68, DOI: 10.3109/03009739609178913
Article is in public domain.
"The neutralization of hydrogen ions (H+) which is caused by other buffer systems in the serum is not revealed in the determination of standard bicarbonate. Of the anions in the plasma, in practice only HC03- and protein- , form a weak acid with H+ and consequently are able to enter into the buffer system within the pH range in question. This constitutes the "buffer base" (BB) in serum and is normally equivalent to 41.7 mmol/L (17 mmol/L of which is protein). When H+ is neutralized, BB decreases. Thus BB provides a principle of the non-respiratory component in the acid-base balance (18,20,21). However, an appreciable part of the metabolic as well as the respiratory supply of hydrogen ions is buffered by Hb in the red blood cells. The value of BB in whole blood (NBB) thus vanes with the haemoglobin (Hb) value, so that for each g/L of Hb the value increases with 0.042 mmol/L. If NBB for plasma is 41.7, the corresponding value for blood with a Hb concentration of 120 g/L = 41.7 + 120 . 0.042 = 46.7 mmol/L"