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

Diagnostic Criteria for Diabetic Ketoacidosis (DKA)

According to the American Diabetes Association guidelines, DKA is diagnosed when all three criteria are present: blood glucose >250 mg/dL, arterial pH <7.3, serum bicarbonate <15 mEq/L, and moderate ketonemia or ketonuria. 1

Essential Diagnostic Criteria

DKA diagnosis requires the presence of:

1. Hyperglycemia: Blood glucose >250 mg/dL

   • Note: Recent guidelines have de-emphasized the strict glucose threshold due to increasing recognition of euglycemic DKA 2
   • Euglycemic DKA can occur with glucose <250 mg/dL, particularly in patients using SGLT2 inhibitors, during pregnancy, or in states of starvation 3

2. Metabolic Acidosis:

   • Arterial pH <7.3
   • Serum bicarbonate <15 mEq/L
   • Elevated anion gap (>10 mEq/L) 2

3. Ketosis:

   • Elevated serum ketones (preferred method) or
   • Positive urine ketones 1, 2

Severity Classification

The American Diabetes Association provides a severity classification system for DKA 1:

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

Additional Diagnostic Considerations

• Laboratory evaluation should include:

  • Electrolytes, phosphate, BUN, creatinine
  • Urinalysis
  • Complete blood count with differential
  • A1C
  • Electrocardiography 2

• Additional tests to consider based on clinical presentation:

  • Amylase, lipase, hepatic transaminase levels
  • Troponin, creatine kinase
  • Blood and urine cultures
  • Chest radiography 2

Special Considerations

1. Euglycemic DKA:

   • Defined as DKA with serum glucose <250 mg/dL
   • Most common in patients with:
     • SGLT2 inhibitor use
     • Pregnancy (up to 2% of pregnancies with pregestational diabetes)
     • Starvation
     • Chronic liver disease
     • Infection
     • Alcohol use 1, 3
   • Requires the same diagnostic approach but with awareness that glucose may not be markedly elevated

2. Resolution Criteria:

   • DKA is considered resolved when:
     • Glucose <200 mg/dL
     • Serum bicarbonate ≥18 mEq/L
     • Venous pH >7.3 1

Common Pitfalls in DKA Diagnosis

1. Missing euglycemic DKA: Always check for ketones and assess acid-base status in patients with diabetes presenting with symptoms of DKA, even if blood glucose is <250 mg/dL.

2. Overlooking DKA in new-onset diabetes: About one-third of DKA cases occur in individuals without a prior diabetes diagnosis 4.

3. Failure to recognize clinical symptoms: Common symptoms include polyuria, polydipsia (98%), weight loss (81%), fatigue (62%), dyspnea (57%), nausea, vomiting (46%), abdominal pain (32%), and preceding febrile illness (40%) 4.

4. Inadequate monitoring: Once DKA is diagnosed, hourly monitoring should include vital signs, neurological status, blood glucose, and fluid input/output, with electrolytes, BUN, creatinine, and venous pH checked every 2-4 hours 1.

By following these diagnostic criteria and being aware of special considerations, clinicians can accurately diagnose DKA and initiate appropriate treatment to reduce the historically significant mortality rate of 2-5% 1.