Thyroid gland is a tiny butterfly-shaped organ that regulates the key processes to ensure our wellbeing. A disorder of this thyroid can severely affect the quality of life. Routine check ups and testing on the functioning of the gland can assist in early diagnosis of thyroid disorders. Thyroid produces two major hormones which include, Thyroxine (T4) and Triiodothyronine (T3). These thyroid hormones control and regulate how your body uses energy. Thyroid-stimulating hormone (TSH) is produced by the pituitary gland that signals the thyroid to produce T3 and T4. When there is less free T3 and T4 in the blood, the pituitary senses the low levels and starts making more TSH. Generally, T3 and T4 levels increase during pregnancy and TSH levels decrease. Such conditions make TSH test necessary. The test can also detect thyroid disorder even before one may experience the symptoms (subclinical thyroid disease).