Iori Koizumi, Hirotaka Kondo
Interpretation of altered T4 concentrations in hedgehogs remains complex.
OBJECTIVE: To characterize total T4 concentrations and support clinical interpretation of T4 measurements in African pygmy hedgehogs.
METHODS: This retrospective, observational study evaluated T4 concentrations in hedgehogs presented to a primarily first-opinion exotic animal practice from October 2023 through November 2025. Thyroxine concentrations were measured using an enzyme immunoassay (EIA)-based point-of-care analyzer. A clinically screened subgroup (n = 15) was defined using clinical, imaging, and laboratory criteria to characterize the observed T4 range. Exploratory subgroup comparisons were performed to evaluate associations between T4 concentrations and predefined clinicopathologic categories. A subset of samples was additionally analyzed using a chemiluminescent EIA (CLEIA)-based system to assess agreement between the EIA and CLEIA methods.
RESULTS: 68 hedgehogs were included. The observed T4 range in the clinically screened subgroup measured using the EIA analyzer was 0.9 to 4.4 μg/dL. Eighteen animals had T4 concentrations exceeding the highest observed value in the clinically screened subgroup. No significant associations were identified between circulating T4 concentrations and predefined clinicopathologic categories. Agreement between EIA and CLEIA measurements was high (intraclass correlation coefficient [3, 1], 0.920; 95% CI, 0.848 to 0.959), although proportional bias was observed.
CONCLUSIONS: Interpretation of altered T4 concentrations in hedgehogs remains complex.
CLINICAL RELEVANCE: T4 measurement using an EIA analyzer may be clinically useful in hedgehogs; however, high T4 concentrations should be interpreted cautiously in conjunction with clinical findings and concurrent disease because altered T4 concentrations may reflect diverse clinical conditions rather than primary thyroid disease alone.