Which laboratory pattern characterizes diabetic ketoacidosis?

• A. Hyperglycemia with anion-gap metabolic acidosis and positive serum or urine ketones
• B. Hypoglycemia with normal anion gap
• C. Hyperglycemia with a non-anion-gap metabolic acidosis and negative ketones
• D. Normal glucose with lactic acidosis

Answer: (A)

Diabetic ketoacidosis presents with high blood glucose, an elevated anion-gap metabolic acidosis, and positive ketones in serum or urine. This pattern stems from insulin deficiency and increased counterregulatory hormones, which promote lipolysis and ketogenesis. Free fatty acids are converted to ketone bodies (like acetoacetate and beta-hydroxybutyrate), these acids accumulate and drive the metabolic acidosis, and the lack of insulin plus excess glucose production leads to marked hyperglycemia. The presence of ketones confirms ketoacidosis, and the elevated anion gap reflects these ketoacid products.

Other patterns don’t fit DKA: hypoglycemia with normal anion gap isn’t characteristic of DKA, which features hyperglycemia and anion-gap acidosis; hyperglycemia with a non-anion-gap acidosis and negative ketones suggests a different acid-base disorder; and normal glucose with lactic acidosis points to a lactic rather than ketoacidosis process.