What does elevated β‑hydroxybutyrate with 3+ urine ketones and a normal arterial pH indicate, and how should it be managed?

Elevated β-Hydroxybutyrate with Normal pH Indicates Euglycemic or Starvation Ketosis

This presentation most likely represents euglycemic ketosis (starvation ketosis, alcoholic ketoacidosis, or SGLT2 inhibitor-associated ketosis) rather than diabetic ketoacidosis, since DKA by definition requires arterial pH <7.30. 1

Diagnostic Clarification

The key distinguishing feature here is the normal arterial pH. According to established diagnostic criteria for DKA, you need ALL three components 1:

• Plasma glucose ≥250 mg/dL
• Arterial pH <7.30 (or bicarbonate <15-18 mEq/L depending on severity)
• Positive ketones

Your patient has ketones but normal pH, which excludes DKA by definition.

What This Actually Represents

Differential diagnosis of ketosis without acidosis:

1. Starvation ketosis - Most common benign cause

   • Serum bicarbonate typically remains >18 mEq/L 1
   • β-hydroxybutyrate elevated but usually <3-4 mmol/L
   • Glucose normal to mildly elevated (rarely >250 mg/dL)

2. Alcoholic ketoacidosis (AKA) - Can present with normal to low glucose

   • Clinical history is key differentiator 1
   • May have profound acidosis OR minimal acidosis depending on timing
   • Glucose ranges from hypoglycemia to mildly elevated

3. Early/resolving DKA - If patient already received treatment

   • β-hydroxybutyrate clears more slowly than pH normalizes
   • Urine ketones persist even longer than blood ketones 1, 2

Critical Management Point

Do NOT rely solely on urine ketones or β-hydroxybutyrate to guide treatment decisions. The nitroprusside method used for urine ketones only detects acetoacetate and acetone, NOT β-hydroxybutyrate (the predominant ketone body) 1. During treatment, β-hydroxybutyrate converts to acetoacetate, which can falsely suggest worsening ketosis 1.

Immediate Assessment Required

Check these parameters immediately:

• Serum bicarbonate and anion gap - If bicarbonate >18 mEq/L and normal anion gap, this is NOT DKA 1
• Venous pH (adequate alternative to arterial) - Should be ≥7.3 1
• Blood glucose - Helps differentiate causes
• Clinical history - Alcohol use, recent food intake, medication history (SGLT2 inhibitors)

Management Algorithm

If bicarbonate >18 mEq/L and pH >7.30:

• This is NOT DKA requiring aggressive treatment
• Address underlying cause (nutrition if starvation, thiamine/dextrose if alcoholic)
• Monitor but do not treat as DKA

If bicarbonate 15-18 mEq/L (borderline):

• Consider mild DKA even with "normal" pH
• May warrant closer monitoring and possible insulin therapy
• Recheck acid-base status in 2-4 hours 1

Common Pitfall to Avoid

The most dangerous error is over-relying on ketone measurements alone. Recent evidence confirms that β-hydroxybutyrate correlates poorly with pH (r = -0.44) and bicarbonate (r = -0.49), meaning 22 of 133 patients with significant acidosis (HCO₃ <18 mmol/L) were NOT hyperglycemic or significantly ketonemic 3. Always measure pH and/or bicarbonate in suspected DKA regardless of glucose or ketone levels 3.

The discordance between elevated β-hydroxybutyrate (3+ urine ketones) and normal pH specifically indicates ketone production without metabolic decompensation—address the underlying cause rather than treating as DKA.