Normal ABG Values Related To Oxygenation and HCO3 Buffering

The first portion of an ABG assay usually reports pH, pO2 and pCO2 The partial pressure of O2 and CO2 is expressed as either kilopascals (kPa) or millimetres of mercury (mm Hg). Normal values (on inspired room air) are as follows:

pH 7.350-7.450


  kPa mm Hg
pCO2 4.67-6.00 35-45
pO2 10.67-13.33 80-100


Bicarbonate 23-28 mmol/L
Base excess -2 to +2 mmol/L

The base excess is calculated from the other values. It indicates the amount of surplus or deficit base [A-] within the blood. It is only useful in determining the metabolic component of the acid-base disorder.

Post a comment

Leave a Comment