* In patients with hyperthyroidism, there will be fewer available binding sites on TBG (due to the increased circulating T3 / T4). This will lead to an increased thyroid hormone binding ratio.
* In patients with hypothyroidism, there will be more free binding sites on TBG (due to the decreased amount of circulating T3 / T4) and as such the THBR will be decreased.
* In general, High with High thyroid activity and Low with Low thyroid activity.