In diabetic ketoacidosis, which arterial blood gas finding supports the diagnosis?

• A. Arterial pH 7.45 With Normal Bicarbonate
• B. Arterial pH 7.0 With Low Bicarbonate
• C. Arterial pH 7.2 With Bicarbonate 14 mEq/L
• D. Arterial pH 7.4 With Bicarbonate 24 mEq/L

Answer: (C)

Diabetic ketoacidosis causes a metabolic acidosis from ketoacid accumulation, so the arterial blood gas shows acidemia with a low bicarbonate. The pH is reduced and the bicarbonate is decreased because the ketoacids lower the serum buffering capacity. The pattern of arterial pH 7.2 with bicarbonate 14 mEq/L is a classic metabolic acidosis with reduced HCO3−, which fits the expected ABG in DKA. The other options either show normal pH and bicarbonate (no acidosis) or a more extreme acidemia that isn’t as typical for DKA, so they don’t align as well with the common ABG presentation of this condition.