Base Excess

Used in assessing acid-base status



Base excess is defined as the amount of strong acid that must be added to each liter of fully oxygenated blood to return the pH to 7.40 at a temperature of 37°C and a pCO2 of 40 mmHg (5.3 kPa), while a base deficit (ie. a negative base excess) is defined by the amount of strong base that must be added.

The formula for base deficit is as follows:

Base excess = 0.02786 X pCO2 X 10^(pH - 6.1) + 13.77 X pH - 124.58


Siggaard-Andersen O.

Scandinavian Journal of Clinical and Laboratory Investigation 1971, 27 (3): 239-45

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1. pCO₂

mm Hg
0/2 completed