A compound with a molecule containing the bicarbonate group HCO3- ; the ion remaining after the first dissociation of carbonate acid Bicarbonate is the standard base used in HD, a concentration of 35 mmol/L or above being necessary to normalize pre-dialysis serum bicarbonate. Unlike acetate, bicarbonate solution is not bactericidal and has to be supplied separately from the other constituents of dialysis fluid Bicarbonate has a similar molecular weight to urea so bicarbonate transfer into blood will be proportional to Kt/V and the bicarbonate concentration gradient across the membrane