Typical Random Blood Glucose in Diabetic Ketoacidosis
The typical random blood glucose in a patient with diabetic ketoacidosis is greater than 250 mg/dL (13.9 mmol/L), which is one of the three core diagnostic criteria required for DKA diagnosis. 1, 2, 3
Core Diagnostic Criteria for DKA
The American Diabetes Association defines DKA by the simultaneous presence of all three of the following criteria:
- Hyperglycemia: Blood glucose >250 mg/dL (13.9 mmol/L) 1, 2, 3
- Metabolic acidosis: Arterial or venous pH <7.3 and serum bicarbonate <15–18 mEq/L 1, 2, 3
- Ketosis: Positive serum or urine ketones, preferably measured as blood β-hydroxybutyrate 1, 2
Severity Classification Based on Glucose and Acidosis
DKA severity is stratified primarily by the degree of acidosis, but all categories maintain the glucose threshold of >250 mg/dL:
- Mild DKA: Glucose >250 mg/dL, pH 7.25–7.30, bicarbonate 15–18 mEq/L, alert mental status 1, 2
- Moderate DKA: Glucose >250 mg/dL, pH 7.00–7.24, bicarbonate 10–<15 mEq/L, alert to drowsy 1, 2
- Severe DKA: Glucose >250 mg/dL, pH <7.00, bicarbonate <10 mEq/L, stupor or coma 1, 2
Important Exception: Euglycemic DKA
Approximately 10% of all DKA presentations are euglycemic, defined by blood glucose <200–250 mg/dL while still meeting the acidosis and ketosis criteria. 2 This represents a critical diagnostic pitfall that can delay recognition and treatment.
Common Causes of Euglycemic DKA:
- SGLT2 inhibitor use (most common modern cause) 1, 2, 4, 5
- Pregnancy (≈2% of pregnancies in women with pre-existing diabetes) 1, 2, 6
- Reduced caloric intake or prolonged fasting 1, 2, 4
- Recent insulin administration 4, 5
- Heavy alcohol consumption 2, 4, 5
- Chronic liver disease 2, 4, 5
Diagnostic Approach for Euglycemic DKA:
For euglycemic DKA, diagnosis requires either documented hyperglycemia at any point or a known history of diabetes, in addition to the required metabolic acidosis (pH <7.3, bicarbonate <18 mEq/L) and elevated β-hydroxybutyrate. 2
Critical Diagnostic Pitfall to Avoid
Never rely solely on glucose levels to rule out DKA. The absence of marked hyperglycemia can delay diagnosis and treatment, resulting in serious adverse outcomes. 4, 5 Always measure blood β-hydroxybutyrate (the preferred ketone test) when DKA is suspected, regardless of glucose level. 1, 2, 3
Nitroprusside-based urine or serum ketone tests should not be used because they only detect acetoacetate and acetone, completely missing β-hydroxybutyrate—the predominant and strongest ketoacid in DKA. 1, 2, 3
Clinical Context
While the classic presentation involves glucose >250 mg/dL, clinicians must maintain a high index of suspicion for euglycemic DKA, particularly in patients on SGLT2 inhibitors, pregnant women with diabetes, or those with reduced oral intake. 1, 2 The key is to check ketones (preferably β-hydroxybutyrate) whenever metabolic acidosis is present, even if glucose appears normal or only mildly elevated. 1, 2, 5