In people with Graves’ disease, a blood marker called TDA doesn’t seem to predict how much their thyroid is being stimulated — even when they’re not on treatment or when they’re in remission.

Most people with untreated Graves' disease have certain immune proteins in their blood that can affect the thyroid, but not everyone has them.

In people with an overactive thyroid caused by Graves’ disease, a certain blood signal called hTSA shows up more often than another one called TDA, which might mean it's a better clue for doctors to spot the disease.

Some people with certain types of thyroid inflammation (like Hashimoto's or subacute thyroiditis) can have a substance called TDA in their blood, but it doesn't actually turn on the thyroid like it does in Graves’ disease — so TDA might not mean the thyroid is being overstimulated.

When someone has Graves’ disease, their thyroid hormones get too high, which tells the brain to stop making a hormone that stimulates the thyroid — so that hormone ends up being very low or even missing in blood tests.