Abstract

Objective: Current criteria for the diagnosis of diabetic ketoacidosis (DKA) are limited by their non-specificity (serum bicarbonate [HCO₃] and pH) and qualitative nature (the presence of ketonemia/ketonuria). The present study was undertaken to determine whether quantitative measurement of a ketone body anion could be used to diagnose DKA.

Research Design and Methods: A retrospective review of records from hospitalized diabetic patients was undertaken to determine the concentration of serum β-hydroxybutyrate (βOHB) that corresponds to a HCO₃ of 18 meq/L, the threshold value for diagnosis in recently-published consensus criteria. Simultaneous admission βOHB and HCO₃ values were recorded from 466 encounters, 129 in children and 337 in adults.

Results: A HCO₃ level of 18 meq/L corresponded with βOHB levels of 3.0 and 3.8 mmol/L in children and adults, respectively. Using these threshold βOHB values to define DKA, there was substantial discordance (∼20% or greater) between βOHB and conventional diagnostic criteria using HCO₃, pH and glucose. In patients with DKA, there was no correlation between HCO₃ and glucose level on admission, and a significant but weak correlation between βOHB and glucose (P < 0.001).

Conclusions: Where available, a serum βOHB ≥3.0 and ≥3.8 mmol/L in children and adults, respectively, in the presence of uncontrolled diabetes can be used to diagnose DKA and may be superior to serum HCO₃ for that purpose. The marked variability in the relationship between βOHB and HCO₃ is likely due to the presence of other acid-base disturbances, especially hyperchloremic, non-anion gap acidosis.