The first step in ABG interpretation is to look at the pH. Normal blood pH is 7.4, plus or minus 0.05, forming the range 7.35 to 7.45. If blood pH falls below 7.35 it is acidic. If blood pH rises above 7.45, it is alkalotic. ... 6 Easy Steps to ABG Interpretation. pH7.35-7.45 Base Excess+ or – 2 4 more rows Nov 27, 2019