What happens when thyroid stimulating hormone goes up?

TSH increase: Thyroid stimulation hormone (TSH) is released by the pituitary gland in response to the amount of thyroid hormone sensed in the blood. If the blood level of thyroid hormone is low then the pituitary increases the amount of TSH into the blood in order to get the thyroid to release more thyroid hormone. Therefore a rising or increasing TSH may indicated a failing or under functioning thyroid.

TSHIT: This usually indicates that the thyroid gland is failing ie primary hypothyroidism. In rare cases elevated TSH can be due to a pituitary tumor that can lead to hyperthyroidism.