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

Abstract

BackgroundContinuous 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).ObjectivesAssess FSL2 accuracy in cats with hypoglycemia.AnimalsNine healthy, purpose‐bred cats.MethodsHyperinsulinemic‐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 < .05 considered significant).ResultsOverall, BG and IG correlated strongly (r = 0.83, P < .0001) in stable glycemia and moderately at all rates of change (r = 0.69, P < .0001). Interstitial glucose concentration underestimated BG in euglycemia, but the BG‐IG difference was progressively smaller as BG decreased (12.9 ± 12.2, 8.8 ± 11.2, −3.2 ± 7.4, and −7.8 ± 5.2 mg/dL in the ranges of 80‐120 [n = 64], 60‐79 [n = 29], 50‐59 [n = 71], and 29‐49 mg/dL [n = 53], respectively).ConclusionsAlthough IG underestimates BG throughout most of the hypo‐euglycemic range, IG generally overestimates BG in marked hypoglycemia (<60 mg/dL). It is therefore imperative to evaluate FSL2 results in this critical range with caution.

Evaluation of the appropriateness of using a continuous glucose monitoring system and a point-of-care glucometer for measuring blood glucose in horses

“…Our results do not corroborate their observation, as we found the correlation between the FL and the gold standard to be weaker, with a correlation coefficient of 0.56. This finding also differs from previous results where the correlation between the FL and a BGC measurement system is reported to be good, with correlation coefficients ranging between 0.88 and 0.84 in dogs [22,23,25] , 0.69 and 0.93 in cats [28][29][30][31] , and 0.92 and 0.96 in humans [18,20] . In addition, the MARD in our study was 35.35 %, which is much higher than in other studies, where the MARD ranged from 17-25.2 % in dogs [23,25] , 14.9 % in cats [31] , and 11.8-16.7 % in humans [18][19][20][21]36,53] .…”

“…In addition to intensive validation and usage in humans [16][17][18][19][20][21] , the FreeStyle Libre™ a (FL) has been validated in dogs [22][23][24][25][26][27] , cats [28][29][30][31] and horses [32][33][34] .…”

Accuracy of Abott Freestyle Libre versus Dexcom G6 in a patient with pre-diabetes: a case report and review of literature

“…In the ndings presented in this report, the peak glucose levels after meal ingestion were also approximately 60 minutes after ingestion (Figs. 1,3,4,5). CGMs may be valuable in comparing the time taken to reach peak glucose levels based on the diet consumed (pasta vs. rice vs. bread).…”

“…The newer versions, FreeStyle Libre 2 or 3, are recommended, offering enhancements like alarms for high or low glucose levels and more frequent glucose measurements (every 1 minute). Despite these updates, the fundamental technology remains consistent (3). Several comparative reports evaluating glucose trends between FreeStyle Libre (original and versions 2) and other CGMs, including G6, in various speci c circumstances suggest that FreeStyle Libre is less accurate under certain conditions (2, 4, 5, 6).…”

“…. Conversely, pre-meal glucose levels exhibited comparability and accuracy in both devices (Figs 1,2,3,4,5)…”