Problem: A 38-year-old overweight man with a history of severe autism is brought into clinic by his mother with a two-week history of polydipsia, polyuria, and increased lethargy with new nausea and vomiting starting the day prior. He is tachycardic, tachypneic, normotensive, and minimally interactive. He has no known history of diabetes but is noted to have unmeasurable hyperglycemia with point-of-care testing. What additional clinical finding would suggest a diagnosis of diabetic ketoacidosis (DKA) over a diagnosis of hyperosmolar hyperglycemic state (HHS) once serum labs are drawn?