What are the diagnostic criteria for diabetic ketoacidosis (DKA)?

Diagnostic Criteria for Diabetic Ketoacidosis (DKA)

The diagnostic criteria for diabetic ketoacidosis (DKA) include blood glucose >250 mg/dL, arterial pH <7.3, serum bicarbonate <15 mEq/L, and moderate ketonemia or ketonuria, as established by the American Diabetes Association. 1

Core Diagnostic Criteria

• Blood glucose >250 mg/dL (although this criterion has been de-emphasized in recent guidelines due to the increasing recognition of euglycemic DKA) 1, 2
• Arterial pH <7.3 1, 3
• Serum bicarbonate <15 mEq/L 1, 3
• Elevated serum ketones (preferred) or urine ketones 1, 2
• Anion gap >10 mEq/L 2

Classification of DKA Severity

DKA can be classified into three severity levels based on the following parameters:

Parameter	Mild	Moderate	Severe
Arterial pH	7.25-7.30	7.00-7.24	<7.00
Bicarbonate (mEq/L)	15-18	10-14	<10
Mental Status	Alert	Alert/drowsy	Stupor/coma

1

Important Clinical Considerations

Euglycemic DKA

• Euglycemic DKA is defined as DKA with blood glucose <250 mg/dL (or even <200 mg/dL) 4, 5
• Risk factors for euglycemic DKA include:
  • Recent insulin use
  • Decreased caloric intake/starvation
  • Pregnancy
  • Alcohol consumption
  • Chronic liver disease
  • Use of SGLT2 inhibitors 4, 2, 5
• Despite normal glucose levels, euglycemic DKA remains a medical emergency requiring prompt treatment 4

Common Presenting Symptoms

• Polyuria and polydipsia (98%)
• Weight loss (81%)
• Fatigue (62%)
• Dyspnea (57%)
• Vomiting (46%)
• Preceding febrile illness (40%)
• Abdominal pain (32%)
• Polyphagia (23%) 3, 2

Diagnostic Evaluation

Essential Laboratory Tests

• Serum glucose
• Arterial or venous pH
• Serum bicarbonate
• Serum ketones (preferred over urine ketones)
• Electrolytes with calculation of anion gap
• Blood urea nitrogen and creatinine
• Complete blood count
• Urinalysis 1, 2

Additional Tests to Consider

• A1C (to differentiate new-onset from established diabetes)
• Electrocardiography
• Amylase and lipase (to evaluate for pancreatitis)
• Blood and urine cultures (if infection suspected)
• Chest radiography (if respiratory symptoms present) 2

Resolution Criteria

DKA is considered resolved when:

• Glucose levels <200 mg/dL
• Serum bicarbonate ≥18 mEq/L
• Venous pH >7.3 1

Common Pitfalls and Caveats

1. Missing euglycemic DKA: Don't rule out DKA based solely on normal or mildly elevated blood glucose levels, especially in patients taking SGLT2 inhibitors 4, 2, 5

2. Delayed diagnosis: About one-third of DKA cases occur in individuals without a previous history of diabetes, so consider DKA in any patient with unexplained metabolic acidosis 3

3. Overlooking precipitating factors: Always search for and treat the underlying cause of DKA (infection, missed insulin doses, new-onset diabetes, etc.) 1, 2

4. Cerebral edema risk: This is a rare but potentially fatal complication, especially in children (0.7-1.0%), requiring vigilant monitoring during treatment 1

5. Electrolyte imbalances: Hypokalemia is a frequent complication (approximately 50%) during DKA treatment that requires careful monitoring 1