T3 Uptake

The T3 Uptake test helps doctors understand how many binding sites are available in the blood for thyroid hormones. These sites are like special spots where thyroid hormones can attach and be useful to the body. When the number of these spots changes, it can tell doctors something about your health.

When the T3 Uptake is low, it might be because of pregnancy, taking estrogen (a type of hormone), having too much protein in the blood, or a rare condition called acute intermittent porphyria. On the other hand, if the T3 Uptake is high, it could be due to taking androgens (another type of hormone), having too much protein in the blood, feeling a lot of stress, or having a problem with your liver like acute liver disease.

It’s important to look at this test along with another test that measures the level of a hormone called thyroxine. Together, these tests help doctors get a clearer picture of how your thyroid is working.