Assessment of the FreeStyle Libre 2 interstitial glucose monitor in hypo- and euglycemic cats

Abstract

Background: Continuous glucose monitoring systems have been validated for eu- and hyperglycemic cats. The FreeStyle Libre 2 (FSL2) is sufficiently accurate in people during hypoglycemia to guide critical treatment decisions without confirmation of blood glucose concentration (BG). Objectives: Assess FSL2 accuracy in cats with hypoglycemia. Animals: Nine healthy, purpose-bred cats. Methods: Hyperinsulinemic-hypoglycemic clamps were performed by IV infusion of regular insulin (constant rate) and glucose (variable rate). Interstitial glucose concentration (IG), measured by FSL2, was compared to BG measured by AlphaTrak2. Data were analyzed for all paired measurements (n = 364) and separately during stable BG (≤1 mg/dL/min change over 10 minutes). Pearson's r test, Bland-Altman test, and Parkes Error Grid analysis respectively were used to determine correlation, bias, and clinical accuracy (P <60 mg/dL). It is therefore imperative to evaluate FSL2 results in this critical range with caution.