What is the normal base excess (BE) range?

• A. -4 to 0
• B. -2 to +2
• C. 0 to +4
• D. -6 to +6

Answer: (B)

Base excess shows how much buffering base is present in the blood, reflecting the metabolic component of acid–base balance. A normal value is about -2 to +2 mEq/L, meaning the blood’s buffering capacity is within the typical range. When base excess is positive, there is an excess of base (metabolic alkalosis or bicarbonate retention); when it is negative, there is a deficit of base (metabolic acidosis). The range -2 to +2 best represents normal buffering; ranges that extend more to one side would imply abnormal metabolic status, while an overly wide range like -6 to +6 would obscure these distinctions.