Use of the "FreeStyle Libre" glucose monitoring system in diabetic cats

The aim of this study was to assess the "FreeStyle Libre" flash glucose monitoring system regarding its measurement accuracy and tolerability in cats. Results from 66 sensors applied to 34 predominantly diabetic cats are included. The behaviour during the attachment, wearing, and removal of the sensor and the skin site of attachment were assessed. Blood samples were regularly collected for comparative measurements (hexokinase method). Minimal signs of discomfort were noted, although the sensor was additionally fixed using individual skin stitches. Sensors, which stopped working in situ (70% [46/66]), had a median functional life of 8.3 (1.6-14) days. Skin reactions on the adhesive surface occurred after removal of 39% (23) of 59 sensors with assessable skin reaction (mild erythema: n = 21; superficial dermatitis: n = 2). Due to the upper limit of the measurement range of 27.8 mmol/l (500 mg/dl), the reading device displayed "Hi" in 62% (17/34) of cats repeatedly and/or for periods >1 h. Results were highly correlated with those of the reference method (r_S = 0.90, n = 359). 67.7% (243/359) of the "FreeStyle Libre" measurement values had a maximum deviation of 15% from reference measurements and 99.4% (357/359) were within the zones A and B of Parkes Consensus error grid analysis. In conclusion, the device proved to be practicable, less stressful for the animals and generated in general acceptable results. Although the upper limit of the measurement range is a limiting factor, the device promises to significantly facilitate the management of diabetic cats.