Why get tested?
To help evaluate thyroid gland function; to help diagnose hypothyroidism or hyperthyroidism; to screen for hypothyroidism in newborns

When to get tested?
Usually ordered in response to an abnormal TSH test result or when a patient has symptoms of hyper- or hypothyroidism; commonly performed on newborns

Sample required?
A blood sample drawn from a vein in the arm or from pricking the heel of an infant