Lactate and lactic acid are not the same. They are opposites. It is typical for total lactate, acid and base lumped together to be considered a useful parameter. This simplistic view is considered good enough for the surviving sepsis protocols. Rising total Lactate, acid and base together is considered an independent predictor of the state of metabolism. Simplistically we do not need to consider the ration of acid to base, only the total. This is indeed confusing. Those who consider that lactic acid and lactate base are not the same are maligned as, “not with the guidelines”. A lactate of 4 is worse that 2 all else being equal which is never the case. There will always be a ratio of lactic acid to lactate as a base. The more lactic acid predominates acid the worse the situation is. For simplicity this ratio is ignored and the total is reported as lactate.

Although lactic acid and lactate are reported as lactate these are actually opposites, acid and conjugate base. The more lactate pared with an inert cation such as sodium there is the more pH will go up and the more lactic acid there is the more the pH will go down. Both are carbohydrates with 3 carbon atoms which makes them similar in that regard but they are otherwise different and actually opposites. The important characteristic is how they affect hydrogen ion concentration, that is pH, each in the opposite direction.