Which laboratory finding is most indicative of diabetic ketoacidosis (DKA)?

Rationale: A. Increased serum bicarbonate level: In diabetic ketoacidosis, bicarbonate levels are decreased because bicarbonate is consumed as it buffers the excess ketone acids. An increased bicarbonate level would not be consistent with DKA. B. Decreased blood pH: The accumulation of ketone bodies in DKA leads to metabolic acidosis. A decreased blood pH, typically below 7.35, is one of the most definitive laboratory findings indicating diabetic ketoacidosis. C. Elevated blood glucose level: Hyperglycemia is present in DKA, often exceeding 250 mg/dL. However, elevated glucose alone is not specific to DKA since it also occurs in hyperosmolar hyperglycemic state (HHS). The distinguishing factor in DKA is acidosis. D. Elevated blood urea nitrogen (BUN) level: Increased BUN may occur in DKA due to dehydration and reduced renal perfusion. While it supports the diagnosis, it is not the most specific indicator of DKA compared with blood pH changes.