Evaluation of the Accuracy of FreeStyle Libre 2 for Glucose Monitoring in White New Zealand Rabbits.

Background: Studies are currently being conducted on rabbits requiring serial glucose monitoring. The FreeStyle Libre 2 (FSL2), a serial glucose monitoring device, has been validated in humans, dogs and cats, but not in rabbits.

Objectives: This study aimed to evaluate the accuracy of the FSL2 in rabbits.

Methods: Six healthy rabbits were used in this study. Interstitial glucose (IG) was measured using the FSL2, and blood glucose (BG) was measured using a portable blood glucose meter (PBGM); their results were compared with those from a clinical chemistry analyser. For the first 3 h, IG and BG were measured at 1-h intervals. Subsequently, they were measured every 8 h over a 48-h period. Regular insulin 0.2 U/kg was then administered to the rabbits, and IG and BG were measured every 15 min over a 90-min period.

Results: Before insulin treatment, no measurements fell within the hypoglycaemic range (BG < 100 mg/dL). In the euglycaemic range (BG ≥ 100 mg/dL), the PBGM and FSL2 showed 85.7% and 23.8% accuracies, respectively. After insulin treatment, the PBGM showed 95.5% and 81.3% accuracies in the hypoglycaemic and euglycaemic ranges, respectively. The FSL2 showed 68.1% and 37.5% accuracies in the hypoglycaemic and euglycaemic ranges, respectively. Parkes consensus error grid analysis showed that the PBGM and FSL2 had 100% agreement for Zones A (no effect on clinical action) and B (altered clinical action unlikely to affect outcome) in rabbits with and without insulin treatment.

Conclusions: There was limited agreement between the FSL2 and reference standard BG measurements. However, the FSL2 allows clinically acceptable identification of hypoglycaemic states in rabbits.