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TriIodothyronine Free Test

TriIodothyronine Free Test

also known as: FT3 Blood, Free T3 Blood, Free Triiodothyronine, FT3

A free triiodothyronine (free T3) test is used to assess thyroid function in a patient. It is ordered to help diagnose hyperthyroidism and may be ordered to help monitor treatment of a person with a known thyroid disorder. T3 (triiodothyronine) is one of two major hormones produced by the thyroid, a small, butterfly-shaped gland located at the base of the throat. T3 makes up less than 10% of what we call thyroid hormone, while T4 makes up the rest. T3, however, is about four times as strong as T4, and is thought to cause most, if not all, the effects of thyroid hormones.

Patients who take multivitamins, dietary supplements containing biotin or vitamin B7 should not take them 24 hours before the test as it may alter the values. Wearing a short sleeve or sleeveless shirt or T-shirt will be helpful for the technicians to draw blood from the veins.
A free T3 test is performed when someone has an abnormal TSH (Thyroid Stimulating Hormone) test result. It may be done when a person has symptoms suggesting hyperthyroidism, especially if the free T4 level is not elevated. Signs and symptoms may include, Increased heart rate, Anxiety, Weight loss, Difficulty sleeping, Tremors in the hands, Weakness, Light sensitivity, visual disturbances. Free T3 may sometimes be done at intervals to monitor a known thyroid condition. High levels of T3 are seen in earlier cases in Hyperthyroidism (Overactive Thyroid). Concentration of T3 may remain normal in Under active thyroidism. Concentration may remain unchanged during pregnancy. Low levels of T3 are found when the patient has some serious general illness.
For the blood to be drawn, at first the area is cleansed with an antiseptic and tourniquet is placed around the upper arm for pressure. A needle is inserted into the vein and blood is drawn and collected in a vial. Now, the tourniquet is removed and the patient is provided with cotton balls to prevent further bleeding.
Circulating antibodies to thyroid hormones have also been reported to interfere with free hormone immunoassays.
Red-top tube or gel-barrier tube
Type Gender Age-Group Value
All age groups
1.8 - 5.4mcg/dl
Average price range of the test is between Rs.100 to Rs.600 depending on the factors of city, quality and availablity.

Table of Content

What is TriIodothyronine Free Test?
Preparation for TriIodothyronine Free Test
Uses of TriIodothyronine Free Test
Procedure for TriIodothyronine Free Test
Limitations of TriIodothyronine Free Test
Specimen Requirements
Normal values for TriIodothyronine Free Test
Price for TriIodothyronine Free Test
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