Last updated: Tuesday, 14, December, 2010
Thyroid stimulating hormone (TSH). Thyroxine (free) if pituitary disease is suspected. Monitoring: TSH should be maintained within the reference interval ie, thyroid replacement therapy should not cause TSH suppression.
Patients should not be tested at less than monthly intervals, especially if the thyroxine dose has been altered, as the half life of thyroxine is approximately one week.
Testing at 6 monthly intervals is usually sufficient.
Patients with a history of thyroid disease should always have TSH performed prior to anaesthesia/surgery.See also Goitre
If thyroidectomy was performed for thyroid carcinoma, thyroxine therapy should be adjusted to cause suppression of TSH levels.
Hypothyroidism should be detected on Neonatal screening.See also Neonatal screening
Thyroid radioactive iodine uptake studies may be indicated to establish the diagnosis of thyroid aplasia/hypoplasia or to detect ectopic thyroid tissue.
Peripheral resistance to thyroid hormone
TSH and thyroxine (free) are both elevated.