T3-Total Tri Iodothyronine Serum Test

Total T3 test is done along with T4 and TSH to
1. Diagnose thyroid disorders both overt & subclinical
2. Monitoring patients on thyroid replacement therapy
In a very small group of patients only T3 & FT3 is increased.
In pregnancy due to increase in thyroglobulin and decrease in albumin may cause increase of T3 & T4 levels, without actually impacting body functions hence testing FT3 and FT4 is more representative

The main purpose of a T3 test is to diagnose hypothyroidism and hyperthyroidism. It is a condition in which the thyroid gland either makes too little or too much thyroid hormone. The test can also help determine the severity of the condition.

Total T3 test measures levels of FT4 hormone in blood

T3 test is a common medical test. It is useful for the diagnosis of hyperthyroidism. It is a condition in which the body makes too much of the thyroid hormone. A T3 test may be ordered together with a T4 and TSH test to monitor the treatment for thyroid disease.

Total T3 test requires a blood sample. A tourniquet (elastic) band is placed tightly on the upper arm. The patient is then asked to make a fist. This helps in the build-up of blood filling the veins. The skin is disinfected before needle insertion and the blood sample is collected in vacutainer

A healthcare provider will extract a blood sample to be used for testing T3 levels in your body. The blood test reports will provide information about the name of the blood test, the measurement of the blood test result and the normal measurement range of the test. In addition, the reports shall also indicate if the test results are on the normal or abnormal side.. 

High TSH & high T3/FT3 and T4/FT4: Thyroxine replacement therapy; pituitary adenoma; drugs like heparin, amiodarone, beta blockers, steroids; neonates; resistance to thyroid hormones
High TSH & low T3/FT3 and  T4/FT4: Autoimmune thyroiditis, thyroidectomy, post-radiation, iodine deficiency, thyroid infiltrating tumour/ amyloid
Low TSH & Low T3/FT3 and T4/FT4: Central hypothyroidism, non-thyroidal illness
Low TSH & High T3/FT3 and FT4: Grave's disease, toxic multinodular goitre, toxic adenoma, thyroiditis, drugs, hyperemesis gravidarum & hydatiform mole, congenital hyperthyroidism

T3 test will display the level of the hormone in the body. Higher levels of T3 indicate that you have hyperthyroidism. This is an overactive thyroid. It can be because of Grave’s disease, thyroid nodules, or thyroiditis. It can speed up your metabolism. This is why it is not considered safe for your health.

Some of the ways to identify hyperthyroidism are unexplained weight loss, a shaky feeling in the limbs, increased bowel movements and rapid heartbeats. A low level of T3 indicates hypothyroidism. It can be due to certain medicines or an ongoing illness. It is best to reach out to a healthcare provider who can assess the test results.

In the human body, T3 and T4 together help to regulate the metabolic rate, functions of the heart, digestive functions, muscle control, development of the brain and maintenance of bones.

Blood tests are essential for screening purposes. There is little risk associated with undergoing the test. You may experience a slight tenderness at the site of the injection. But usually, it will heal quickly.

The results of total T3 are usually very accurate. Yet, there are some factors. They can interfere with the results of the test. These usually include the consumption of certain medicines before the test. In case the test results come back with a high or low measure, it is best to reach out to a doctor for assessment

This test may be required if you are displaying signs of hypothyroidism such as follows:

• Tiredness/ fatigue
• More sensitivity to cold
• Constipation
• Dry skin
• Weight gain
• Puffy face
• Hoarse voice
• Coarse hair and skin

This test may be required if you are displaying signs of hyperthyroidism such as follows:

·        Anxiety

·        Loss of weight

·        Increased heart rate

·        Sleeping troubles

·        Low tolerance for heat

·        Bulging eyes

·        Frequent bowel movements

In addition, a person may need to get the thyroid test done in the event of hair loss, an increase in appetite, an increase in sweating, menstrual irregularities, palpitations in the heart, insomnia, and problems in concentration.

No special preparation is required before the test. Healthcare providers might restrict the intake of certain medicines which can intervene in the results.

T3 is a thyroid hormone. It plays a significant role in the human body. T4 is yet another significant thyroid hormone. It works in tandem with T3 to regulate the metabolism of the body, activate cells and help other vital organs in functioning properly. A total T3 test helps to measure both, free T3 and bound T3. In contrast, free T3 measures the T3 not attached to proteins.

• Total Triiodothyronine (TT3)
• Thyroid Hormone Test
• Total T3 Test