Table 2 Diagnostic performance of key laboratory tests in DKA-HHS overlap [19, 21, 28]
Test | Parameter | Utility in Overlap |
|---|---|---|
Blood Glucose | > 250 mg/dL (DKA), > 600 (HHS) | Essential, but values can be in the 300–600 mg/dL range |
Serum Osmolality^a^ | > 320 mOsm/kg | Critical for identifying HHS component |
Serum Beta-Hydroxybutyrate (BOHB) | ≥ 3.0 mmol/L | Gold standard for ketosis; superior to urine testing |
Urine Ketones (Nitroprusside) | Positive | Sensitive but non-specific; can underestimate/overestimate |
Venous Blood Gas (VBG) | pH < 7.3, HCO₃⁻ <18 mEq/L | Practical alternative to ABG for diagnosing acidosis |
Anion Gap | > 12 mEq/L | Supports presence of metabolic acidosis |
Diagnosis of Overlap Syndrome | Meets both: (1) BOHB ≥ 3.0 mmol/L AND pH < 7.3; (2) Osmolality > 320 mOsm/kg | Provides a clear, actionable definition for clinicians |