If a CGM isn’t possible, what are some tools to help you monitor diabetic cats long term?

Savannah Tobin, Jocelyn Mott, Chen Gilor,

Evaluating the correlation between serum fructosamine concentration and interstitial glucose concentration in cats with diabetes mellitus,

Journal of Veterinary Internal Medicine, Volume 40, Issue 3, May-June 2026, aalag104, https://doi.org/10.1093/jvimsj/aalag104

Abstract

Background

Continuous monitoring of interstitial glucose concentration (CGM) is used in cats with diabetes mellitus (DM), but challenges remain with cat tolerance, affordability, global accessibility, and owner technophobia. Serum fructosamine (SF) concentration is an alternative, but its correlation to CGM has not been assessed.

Hypothesis/Objectives

Serum fructosamine concentration correlates with mean interstitial glucose in cats.

Animals

Twelve client-owned cats with DM.

Methods

This was a prospective cohort study. Cats with poorly controlled DM were treated with insulin with the goal of improving glycemic control, while monitored using CGM and SF concentration for a period of 6-12 weeks. At each recheck of SF concentration, CGM was applied. Mean interstitial glucose concentration was calculated over 72 h (IG72h) surrounding SF concentration measurement. Paired IG72h and SF concentration measurements were collected at the time of enrollment, and at 3- to 6-week and 9- to 12-week time points. Correlation was evaluated by Spearman’s rank test and simple linear regression. Serum fructosamine concentration was categorized based on reference laboratory interpretive guidelines, then by physiologically relevant cut-points of IG72h and evaluated for overlap between groups.

Results

There was a strong correlation between SF concentration and IG72h (r = 0.87; [95% CI, 0.73-0.94]; P < .0001; R2 = 0.81). When SF concentration was categorized based on reference laboratory interpretive guidelines, there was significant overlap between groups. This effect was also seen when categorizing SF concentration by physiologically relevant cut-points of IG72h.

Conclusions and clinical importance

Trends in SF concentration can serve as a viable monitoring tool to evaluate short-term changes in glycemia when CGM is not an option.