 "Acidaemia" refers unambiguously to the actual change in the pH of the ECF, whereas "acidosis", strictly speaking, refers to "either" a rise in the amount of carbonic acid in the ECF "or" to a decrease in the amount of HCO in the ECF.Either change would "on its own" (i.e.if left "uncompensated" by an alkalosis) cause an acidaemia.