Thyroid abnormalities have been anecdotally reported in red pandas (Ailurus fulgens fulgens); however, definitive diagnosis is hampered by a lack of established reference ranges and validated diagnostic tests. The chemiluminescent assay for canine thyroid stimulating hormone (cTSH) has been validated for use in domestic canids and felids. This study aims to validate the cTSH assay for use in red pandas. Validation was performed via serial dilutions of banked serum samples (n = 15) and both inter- and intra-assay testing. High estimated recoveries and low coefficients of variability indicate that the cTSH assay accurately and consistently measures TSH concentrations in red panda serum. Further studies to generate red panda age and sex TSH reference ranges are indicated.