Diabetic ketoacidosis (DKA) presents with which typical laboratory findings?

• A. High glucose, anion gap metabolic acidosis, positive ketones, dehydration
• B. Low glucose, metabolic alkalosis, negative ketones, dehydration
• C. Normal glucose, non-anion gap metabolic acidosis, dehydration
• D. Hyperglycemia with normal bicarbonate but no ketones

Answer: (A)

The key idea is recognizing the lab pattern of diabetic ketoacidosis: high blood glucose with an anion-gap metabolic acidosis and positive ketones, along with dehydration. In DKA, lack of insulin plus counterregulatory hormones drives fat breakdown and ketone production, so ketones accumulate in blood and urine and bicarbonate is consumed to buffer the acidosis, giving an anion-gap metabolic acidosis. The high glucose comes from increased hepatic glucose production and impaired use, while dehydration arises from osmotic diuresis from the glucose in the urine. So the typical labs are elevated glucose, a low bicarbonate with acidosis (and an elevated anion gap), and positive ketones, with dehydration evident clinically. Other patterns don’t fit because they miss hyperglycemia, the ketone-driven acidosis, or both.