Diagnosing Diabetic Ketoacidosis (DKA) in Type 2 Diabetes

Core Diagnostic Criteria

The American Diabetes Association recommends diagnosing DKA in type 2 diabetics using the same criteria as type 1 diabetes: blood glucose >250 mg/dL, venous pH <7.3, serum bicarbonate <15 mEq/L, and elevated blood β-hydroxybutyrate (β-OHB) 1
The diagnosis requires three components present simultaneously: hyperglycemia, metabolic acidosis, and ketosis 1
Hyperglycemia is defined as blood glucose >250 mg/dL, though this can be absent in euglycemic DKA 1
Metabolic acidosis is defined as venous pH <7.3 and serum bicarbonate <15 mEq/L 1
Ketosis is defined as elevated blood ketones, preferably measured as β-OHB 2, 3

The American Association of Clinical Endocrinologists recommends obtaining a complete metabolic panel, venous blood gas, blood β-hydroxybutyrate (β-OHB), complete blood count, urinalysis, serum osmolality, and electrocardiogram immediately upon presentation 1, 4, 5
Blood β-hydroxybutyrate (β-OHB) is the preferred ketone measurement 2, 3

The Endocrine Society recommends using direct blood β-OHB measurement, NOT urine ketones or nitroprusside-based tests 2, 3
The nitroprusside method only measures acetoacetate and acetone, completely missing β-OHB, which is the predominant ketone in DKA 2, 3

The American College of Endocrinology recommends classifying DKA severity as mild (pH 7.25-7.30, bicarbonate 15-18 mEq/L, alert mental status), moderate (pH 7.00-7.24, bicarbonate 10-15 mEq/L, drowsy/lethargic), or severe (pH <7.00, bicarbonate <10 mEq/L, stuporous or comatose) 1

The American Diabetes Association notes that although DKA is less common in type 2 diabetes, it can occur and requires the same diagnostic approach 2
SGLT2 inhibitors significantly increase DKA risk in type 2 diabetics and commonly cause euglycemic DKA (glucose <250 mg/dL with ketoacidosis) 2

The American Association of Clinical Endocrinologists advises against relying on urine ketones for diagnosis, as they miss β-OHB and can be falsely negative early in DKA 2, 3
The Endocrine Society recommends against dismissing DKA possibility because glucose is <250 mg/dL, as euglycemic DKA is increasingly common, especially with SGLT2 inhibitors 2

The American College of Endocrinology recommends drawing blood every 2-4 hours to measure electrolytes, glucose, venous pH, β-OHB, anion gap, BUN/creatinine, and serum osmolality once DKA is diagnosed 1, 5
Resolution is confirmed when ALL of the following are met: glucose <200 mg/dL, venous pH >7.3, serum bicarbonate ≥18 mEq/L, and anion gap ≤12 mEq/L 1, 5