Acetoacetic acid (AcAc) and 3-beta-hydroxybutyrate (3HB) are the most important ketone bodies produced during diabetic ketoacidosis (DKA), with estimation of urinary AcAc being the preferred method for diagnosing DKA in dogs. A handheld electrochemical sensor that measures blood 3HB concentrations has become available for people, but few reports regarding using 3HB evaluation in DKA-affected dogs exist. This study compared the diagnostic accuracy of this method with estimation of urinary AcAc for diagnosing canine DKA. Blood glucose concentrations, venous blood bicarbonate (HCO3-), anion gap (AG), ketonemia, and ketonuria were evaluated in 72 client-owned dogs. Based on HCO3- and AG, the dogs were divided into 2 groups: those with DKA (n = 25) and those with diabetic ketosis (DK; n = 47). Ketonemia was measured using a handheld electrochemical ketone sensor, and ketonuria was measured using semiquantitative urinary test strips. The study found that using cut-off values of 2.3 and 4.3 mmol/L for ketonemia yielded 100% sensitivity and 100% specificity, respectively, for diagnosing DKA. When measuring ketonuria, a cut-off value of 1+ yielded 92% sensitivity and 40% specificity, while a cut-off value of 3+ yielded 44% sensitivity and 94% specificity. Based on these results, the authors recommend initiating treatment for DKA in dogs with ketonemia >_ 3.5 mmol/L as they are at higher risk for presenting with clinical DKA. Conversely, the risk for DKA is very low with ketonemia < 2.8 mmol/L. Based on dipstick results, the absence of ketonuria did not exclude DKA in dogs, whereas the presence of ketonuria might lead to false-positive diagnosis of DKA. The authors conclude that the handheld electrochemical ketone sensor measuring blood 3HB was more accurate than estimation of urinary AcAc for diagnosing DKA in dogs.

COMMENTARY: This study demonstrates that in-house measurement of 3HB using a portable handheld meter was more accurate than urinary measurement of AcAc in the initial assessment of dogs with DKA versus DK. The study did not examine the role of monitoring ketonemia/ketonuria in the management of patients with DKA or DK undergoing therapy and did not compare the measurement of AcAc via the application of serum to urine test strips versus 3HB in whole blood to estimate ketonemia. The handheld meter provided comparable results to those obtained with a standard enzymatic method adapted for an automated analyzer, was easy to use, and required a small sample size. The use of this meter will need to be evaluated in additional studies designed to address its value in the monitoring of patients undergoing intensive therapy for DKA and DK.

Evaluation of a portable meter to measure ketonemia and comparison with ketonuria for the diagnosis of canine diabetic ketoacidosis. Di Tommaso M, Aste G, Rocconi F, et al. J Vet Intern Med 23:466-471, 2009.