What are the diagnostic criteria for Diabetic Ketoacidosis (DKA)?

Diagnosing Diabetic Ketoacidosis (DKA)

DKA is diagnosed by the triad of hyperglycemia (blood glucose >250 mg/dL), metabolic acidosis (pH <7.3, bicarbonate <15 mEq/L), and elevated ketones in blood or urine, with a beta-hydroxybutyrate (BHB) level of ≥3.0 mmol/L in children and ≥3.8 mmol/L in adults considered diagnostic in the presence of uncontrolled diabetes. 1

Diagnostic Criteria

The three essential components for DKA diagnosis are:

1. Hyperglycemia:

   • Blood glucose typically >250 mg/dL
   • Note: Euglycemic DKA can occur, especially in patients taking SGLT2 inhibitors 1, 2

2. Metabolic Acidosis:

   • Venous pH <7.3
   • Serum bicarbonate <15-18 mEq/L
   • Anion gap >10 mEq/L 3, 1

3. Ketosis:

   • Elevated blood or urine ketones
   • Blood β-hydroxybutyrate (BHB) ≥3.0 mmol/L (children) or ≥3.8 mmol/L (adults) 1

Severity Classification

DKA severity can be classified based on arterial pH and serum bicarbonate levels:

Severity	Arterial pH	Serum Bicarbonate (mEq/L)
Mild	7.25-7.30	15-18
Moderate	7.00-7.24	10 to <15
Severe	<7.00	<10

1

Diagnostic Tests

Initial Laboratory Evaluation

• Blood glucose
• Venous blood gases (pH, bicarbonate)
• Serum electrolytes (sodium, potassium, chloride)
• Blood urea nitrogen (BUN) and creatinine
• Calcium and phosphorous
• Complete blood count
• Urinalysis 3, 1

Ketone Testing

• Blood ketone testing (β-hydroxybutyrate) is preferred over urine ketone testing
• The nitroprusside method (urine ketones) only measures acetoacetic acid and acetone, not β-hydroxybutyrate, which is the strongest and most prevalent acid in DKA 3, 1
• During treatment, β-hydroxybutyrate converts to acetoacetic acid, which may falsely suggest worsening ketosis when using nitroprusside methods 3

Additional Tests to Consider

• Amylase and lipase (to rule out pancreatitis)
• Hepatic transaminase levels
• Troponin and creatine kinase (if cardiac involvement suspected)
• Blood and urine cultures (if infection suspected)
• Chest radiography (if respiratory symptoms present) 2

Clinical Presentation

Common symptoms and signs include:

• Polyuria and polydipsia (most common)
• Nausea and vomiting
• Abdominal pain
• Weight loss
• Severe fatigue
• Dyspnea
• Altered mental status or severe dehydration 3, 2

Monitoring During Treatment

• Blood glucose every 1-2 hours
• Electrolytes, venous pH, and anion gap every 2-4 hours
• Blood β-hydroxybutyrate levels (preferred method for monitoring DKA resolution)
• Avoid using urine or serum ketone levels by nitroprusside method as indicators of response to therapy 3, 1

Resolution Criteria

DKA is considered resolved when:

• Glucose <200 mg/dL
• Serum bicarbonate ≥18 mEq/L
• Venous pH ≥7.3
• Blood β-hydroxybutyrate <1.5 mmol/L (sensitivity 83%, specificity 87%) 3, 1

Common Pitfalls to Avoid

1. Missing euglycemic DKA: Don't rule out DKA based on normal or only moderately elevated glucose levels, especially in patients taking SGLT2 inhibitors 1, 2

2. Relying on urine ketones: Urine ketone tests don't measure β-hydroxybutyrate and may be misleading during treatment as ketone bodies convert from one form to another 3, 1

3. Inadequate monitoring: Failure to regularly monitor electrolytes, glucose, and acid-base status during treatment can lead to complications 3

4. Not identifying precipitating factors: Always search for and address the underlying cause (infection, medication non-compliance, acute illness) 2, 4

5. Overlooking hypokalemia: Insulin therapy can cause potassium shifts, requiring careful monitoring of potassium levels 5

By following these diagnostic criteria and avoiding common pitfalls, clinicians can accurately diagnose DKA and initiate appropriate treatment promptly to reduce morbidity and mortality.