Two human portable glucometers and a veterinary point-of-care glucometer correlate well with a reference laboratory chemistry analyzer for measurement of blood glucose concentrations in dogs.

Objective: Comparison of a veterinary glucometer (AlphaTRAK 2 [AT-2]) and 2 human glucometers (FreeStyle Libre 2 [FS-] and FreeStyle Libre 14 [FS-14]) to an automated, wet-chemistry analyzer (reference analyzer).

Methods: This was a prospective observational study at Tufts Cummings School of Veterinary Medicine between January 2021 and September 2022 and included 187 client and staff-owned dogs. Following venipuncture, 3 glucometers (FS-14, FS-2, and AT-2) were used to measure blood glucose, and the reference analyzer was used to measure serum glucose.

Results: Compared to the reference analyzer, the FS-2 and FS-14 glucometers had a negative bias (mean difference estimates: FS-2, -25.01 mg/dL [95% CI, -60.4 to 10.3]; FS-14, -23.6 mg/dL [95% CI, -60.7 to 13.5]), while the AT-2 glucometer had a positive bias (mean difference estimates: 15.4 mg/dL [95% CI, -41.1 to 72.2]). All glucometers showed significant constant and proportional biases based on Passing-Bablok regression with constant biases of -12.3, -10.05, and -14.25 for the FS-2, FS-14, and AT-2, respectively. Most results were within zone A (FS-2, 50.3%; FS-14, 54.5%; AT-2, 70.1%) and B (FS-2, 49.7%; FS-14, 45.5%; AT-2, 26.2%) of the Clarke error grid. The AT-2 produced values within zone C (1.6%) and zone D (2.1%).

Conclusions: All glucometers correlated with the reference analyzer and were clinically useful. As the AT-2 glucometer produced values in the Clarke error grid zones C and D, serum glucose should be measured when results are unexpected or influence the treatment regimen.

Clinical relevance: Despite potential biases, owners can use FS-2 and FS-14 glucometers to verify sensor readings in dogs using continuous glucose monitoring devices.