Which set of laboratory findings best establishes the diagnosis of diabetic ketoacidosis?
- A Plasma glucose above 600 mg/dL with effective serum osmolality above 320 mOsm/kg and minimal ketosis
- B Random plasma glucose above 200 mg/dL with glycosuria and a normal anion gap
- C Plasma glucose above 250 mg/dL, arterial pH below 7.30, serum bicarbonate below 18 mEq/L, and ketonemia or significant ketonuria ✓
- D Arterial pH below 7.35 with lactate above 5 mmol/L and normal serum glucose
Correct answer: C. Plasma glucose above 250 mg/dL, arterial pH below 7.30, serum bicarbonate below 18 mEq/L, and ketonemia or significant ketonuria
Explanation
DKA is defined biochemically by hyperglycaemia (usually above 250 mg/dL), a low arterial pH below 7.30, bicarbonate below 18 mEq/L, and demonstrable ketones in blood or urine, producing a high anion gap metabolic acidosis. Option A describes hyperosmolar hyperglycaemic state, which features profound hyperglycaemia and osmolality with little ketosis. Option D describes lactic acidosis, where the anion gap is driven by lactate rather than beta hydroxybutyrate.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.