Thyroid Function Test
Thyroid function tests are a series of blood test used to measure how well your thyroid gland is working.
TSH is a hormone that controls thyroid gland activity. It’s typically used as a marker of thyroid health. It is produced by the brain’s pituitary gland, but stimulates production of the hormones triiodothyronine (T3) and thyroxine (T4) in the thyroid gland.
- High TSH levels typically indicate an underactive thyroid gland, which produces too little thyroid hormone. This is known medically as hypothyroidism.
- Low TSH levels typically indicate an overactive thyroid gland, which produces too much thyroid hormone. This is known medically as hyperthyroidism.
