In diabetic ketoacidosis, what are the typical pH and bicarbonate levels?

• A. pH >7.45 and bicarbonate >24.
• B. pH 7.35-7.45 and bicarbonate 22-26.
• C. pH <7.3 and bicarbonate <18 mEq/L.
• D. pH 7.0-7.2 and bicarbonate 10-15.

Answer: (C)

Diabetic ketoacidosis creates an anion-gap metabolic acidosis from accumulating ketone bodies, so the blood becomes acidic and buffering bicarbonate is consumed. The typical pattern is acidemia with a low bicarbonate level: pH below 7.3 and bicarbonate below 18 mEq/L. This combination reflects significant loss of buffering capacity due to ketoacids. Normal pH and bicarbonate would not indicate DKA, and a clearly alkaline or normal-range ABG would also be inconsistent. While severe cases can push pH and bicarbonate even lower, the standard diagnostic thresholds used are pH <7.3 and bicarbonate <18.