Which statement about laboratory findings in DKA and HHNC is NOT true?

In examining the laboratory findings associated with Diabetic Ketoacidosis (DKA) and Hyperglycemic Hyperosmolar Nonketotic Coma (HHNC), it is essential to differentiate the physiological responses in these two conditions.

Severely low serum bicarbonate levels are a hallmark of DKA due to increased ketoacid production, which results from fat metabolism when insulin is deficient. This process leads to a significant accumulation of ketones, causing metabolic acidosis. In contrast, in HHNC, serum bicarbonate levels typically remain normal or only mildly decreased because this condition is primarily characterized by hyperglycemia and the resultant osmotic diuresis without the same degree of ketoacid production. As such, the statement about severely low serum bicarbonate levels being present in both DKA and HHNC is not accurate.

In terms of the other statements, patients with HHNC do exhibit blood glucose levels exceeding 700 mg/dL, serum ketones are primarily present in DKA, and serum osmolality in HHNC is indeed elevated above 350 mOsm/L due to the significant hyperglycemia and dehydration experienced. Understanding these distinctions is crucial for diagnosing and managing these potentially life-threatening conditions effectively.