Both kits (as stated above) are very sensitive, stable and reliable. Strictly follow the company manual protocol and hope you will get the expected standard curve and sample data.
The Mouse Transthyretin (TTR) ELISA kit from CUSABIO may be a good option. One citation was found. More details, please check this page: https://www.cusabio.com/ELISA-Kit/Mouse-TransthyretinTTR-ELISA-kit-110690.html