Can serum β-hydroxybutyrate be used to diagnose diabetic ketoacidosis?

OBJECTIVE-Current criteria for the diagnosis of diabetic ketoacidosis (DKA) are limited by their nonspecificity (serum bicarbonate [HCO ₃] 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 etrospective review of records from hospitalized diabetic patients was undertaken to determine the concentration of serum β-hydroxy-butyrate βOHB) that corresponds to a HCO ₃ level of 18 mEq/l, the threshold value for diagnosis in recently published consensus criteria. Simultaneous admission βOHB and HCO ₃ values were recorded from 466 encounters, 129 in children and 337 in adults. RESULTS-A HCO ₃ level of 18 mEq/l corresponded with βOHB levels of 3.0 and 3.8 mmol/l in children and adults, respectively. With the use of these threshold βOHB values to define DKA, there was substantial discordance (̃≥20%) between βOHB and conventional diagnostic criteria using HCO ₃, pH, and glucose. In patients with DKA, there was no correlation between HCO ₃ and glucose levels on admission and a significant but weak correlation between βOHB and glucose levels (P < 0.001). CONCLUSIONS -Where available, serum βOHB levels ≥3.0 and ≥ mmol/l in children and adults, respectively, in the presence of uncontrolled diabetes can be used to diagnose DKA and may be superior to the serum HCO ₃ level for that purpose. The marked variability in the relationship between ( OHB and HCO ₃ is probably due to the presence of other acid-base disturbances, especially hyperchloremic, nonanion gap acidosis.