Point-of-care β-hydroxybutyrate measurement for the diagnosis of feline diabetic ketoacidaemia.

Abstract

OBJECTIVES: To evaluate accuracy and precision of a hand-held ketone meter measuring &#x3b2;-hydroxybutyrate and to determine its diagnostic performance to rule out ketoacidaemia in diabetic cats. METHODS: The ketone meter was validated by calculating within-day precision at different &#x3b2;-hydroxybutyrate concentrations and by comparison with a laboratory method. To determine its diagnostic performance to diagnose ketoacidaemia, 217 sets of data (venous blood gas analysis and &#x3b2;-hydroxybutyrate measurements) were retrospectively analysed. Sensitivities and specificities were calculated with the help of receiver-operating characteristic curves. RESULTS: The ketone meter reliably detected &#x3b2;-hydroxybutyrate at concentrations >0&#xb7;1 mmol/L and reproducibility was acceptable. Measurements highly correlated with laboratory results (r=0&#xb7;97; P<0&#xb7;001), but a significant negative bias was found at high concentrations. A &#x3b2;-hydroxybutyrate concentration of >2&#xb7;55 mmol/L had a sensitivity of 94% and a specificity of 68% for diagnosing ketoacidaemia. Many cats with high &#x3b2;-hydroxybutyrate concentrations and normal blood pH had an elevated chloride gap suggestive of superimposed hypochloraemic metabolic alkalosis. CLINICAL SIGNIFICANCE: The commercially available point-of-care ketone meter Precision Xtra is a valid tool to measure &#x3b2;-hydroxybutyrate in diabetic cats. Concentration <2&#xb7;55 mmol/L enable ketoacidaemia to be excluded and should lead to redirection of differential diagnoses.