Evaluation of a continuous glucose monitoring system in healthy dairy calves and adult goats.

OBJECTIVE

To determine the accuracy of a continuous glucose monitoring system (CGMS) device by comparing glucose concentrations measured over time as determined by the CGMS to those of the chemistry analyzer (reference method).

ANIMALS: 7 healthy goats and 7 dairy calves.

METHODS

A randomized, crossover design with 3 treatments: control, hypoglycemia, and hyperglycemia. The CGMS device was applied to the neck. Hypoglycemia and hyperglycemia were induced by insulin and xylazine, respectively. Glucose concentrations were measured by the chemistry analyzer CGMS, point-of-care glucometer, and intensive care unit machine at 0 (before treatment), 2, 4, 6, 8, 10, and 12 hours. Agreement between the CGMS and the chemistry analyzer was determined by Bland-Altman plots. The analytical and clinical accuracy of the CGMS was determined using the International Organization for Standardization (ISO) 15197:2013 criteria and the Parkes error grid analysis.

RESULTS

In goats, the CGMS overestimated glucose concentrations during the hypoglycemic, normoglycemia, and hyperglycemia treatments. In calves, the CGMS underestimated glucose concentrations during the hypoglycemic treatment but overestimated glucose concentrations in normoglycemia and hyperglycemic treatments. The CGMS met the ISO clinical accuracy criteria for goats and calves, with > 99% of the glucose measurements in zones A and B of the Parkes grid. However, the CGMS did not meet the ISO 15197:2013 criteria for analytical accuracy.

CLINICAL RELEVANCE: The CGMS evaluated in our study only met the ISO 15197:2013 clinical accuracy criteria, not the analytical accuracy. Therefore, the device might be considered for clinical use.