What is this test?
This is a test used to evaluate the proper functioning of the thyroid gland and monitor thyroid treatment.
 
Sample required
Blood.
 
Patient preparation
If you take thyroid hormone as treatment for thyroid disease, it is recommended that your blood sample be drawn before you take your dose for that day. Acute illness may also affect thyroid testing results so it is generally recommended that thyroid testing be avoided in hospitalized patients. Inform the doctor if you are on any medications, or have any allergies or underlying medical conditions before this test.
 
Turn-around time (How long does it take?)
5 Hours.
 
Basis of the Test
Most of the hormone produced by the thyroid is T4. This hormone is relatively inactive, but it is converted into the much more active T3 in the liver and other tissues. If the thyroid gland does not produce sufficient T4 and T3 (underactive thyroid), due to thyroid dysfunction or insufficient TSH, then the affected person experiences symptoms of hypothyroidism such as weight gain, dry skin, cold intolerance, irregular menstruation, and fatigue. If the thyroid gland produces too much T4 and T3, the affected person may experience symptoms associated with an overactive thyroid (hyperthyroidism), such as rapid heart rate, anxiety, weight loss, difficulty sleeping, tremors in the hands, puffiness around dry, irritated eyes and in some cases, bulging eyes.