Taniska Beharee, Sophie Ashworth, Clara Mattavelli, Ian Ramsey

University of Glasgow, Glasgow, United Kingdom

Objectives

To compare beta-hydroxybutyrate (BHB) concentrations on a new meter (InSight Keto Vet®) with an existing meter (NovaVet blood ketone meter ®) in dogs and cats.

Methods

 In a prospective comparison study using clinical cases, BHB was measured in residual heparinised blood using both ketone meters. Sixty-eight paired BHB readings were obtained from dogs and cats without diabetes mellitus (n=21), with diabetes mellitus (n=36) and with suspected diabetic ketoacidosis (n=11). There were thirty-two paired readings obtained at different time points from 12 patients. The values were compared using Pearson correlation and calculation of bias from a Bland Altman plot.

Results

 The range of measured BHB values was 0 to 5.7 mmol/L. There were seventeen readings greater than 0.5 mmol/l. There was strong correlation between the two meters (r2 = 0.95). The new meter showed a positive average proportional bias (0.04 and 0.35 for all values and values greater than 0.5 mmol/L respectively). For values greater than 0.5 mmol/L, the difference between the two meters ranged from –0.64 to 1.34 mmol/L.

Statement: Impact/ Clinical Significance

The two ketone meters are not interchangeable. The limit of agreement between meters is large enough to be clinically relevant. The simultaneous use of these meters within the same hospital may yield misleading interpretations of ketone levels and trends for the clinician due to differing response ranges between the devices. Future studies assessing the effects of confounding factors on the accuracy of the InSight meter when compared with a reference laboratory are warranted.