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Thyroxine - Free

275
4.7
NABL, NABH, ISO
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Overview
Interpretations
FAQ's

Overview of Thyroxine - Free

What is Thyroxine - Free?

Thyroxine (T4) is a hormone secreted by the thyroid gland (small, butterfly-shaped gland located in front of the neck). The T4 hormone is essential for growth and metabolism. T4 circulates in the blood in two forms: Free form (FT4) and Bound form. Free Thyroxine (T4) test measures the free form of Thyroxine hormone in the blood.

Sample Type

The sample type collected for Thyroxine - Free is: Blood

Preparation for Thyroxine - Free

  • No special preparation required

Why Get Tested for Thyroxine - Free?

  • To diagnose any suspected thyroid disease (Hypothyroidism or Hyperthyroidism)

  • To monitor treatment in patients with thyroid diseases




Understand more about Thyroxine - Free

The thyroid gland secretes the following hormones:

  • Triiodothyronine (T3)

  • Thyroxine (T4)


Thyroid Stimulating Hormone (TSH) is a hormone secreted into the blood by a gland present in the brain (Pituitary gland) and it tells your thyroid gland to make and release the thyroid hormones (T3 & T4) into your blood. The thyroid gland uses iodine from food to make the thyroid hormones.


The thyroid hormones are essential for growth and metabolism. If the thyroid gland produces very high amounts of these hormones (T3 and T4), you may experience symptoms of weight loss, rapid heartbeat, tremors, sweating, anxiety, increased sensitivity to heat etc. and this is known as Hyperthyroidism.

Also, the decreased production of thyroid hormones (T3 and T4) results in Hypothyroidism which may cause symptoms like weight gain, fatigue, slow heart rate, increased sensitivity to cold, depression, dry and thin hair etc.


There is a feedback system in the body to maintain stable amounts of the thyroid hormones (T3 and T4) in the blood. When thyroid hormone levels decrease, the pituitary gland is stimulated to release TSH. This high TSH in turn leads to the release of more thyroid hormones (T3 & T4) from the thyroid gland and vice-versa.

T4 hormone constitutes about 90% of thyroid hormones and circulates in the blood in two forms:

1) Bound form - It is bound to proteins present in blood and this prevents it from entering body tissues.  The three main proteins in the blood that the T4 hormone is bound to are albumin, transthyretin and Thyroxine-binding globulin (TBG), also called Thyroid hormone Binding Globulin (THBG).

 

2) Free form - It enters the body tissues where it's needed and this is the active form. Free Thyroxine (FT4) constitutes only 0.3% of the total T3 hormone.

 

Hence, the T4 hormone can be measured as Free T4 or Total T4. The total T4 includes both bound and free forms circulating in the blood and can be affected by the amount of protein available in the blood to bind to them. Therefore, Thyroxine (T4) Free test is a useful indicator of T4 levels in the blood when binding proteins are increased or decreased.

 

Thyroxine (T4) Free test is also done as a part of the Thyroid Profile Free test which includes two more tests: Thyroid Stimulating Hormone (TSH) and Triiodothyronine (T3) Total.


What Results of Thyroxine - Free mean?

Interpretations


Age

FT4 (pmol/L)

Newborn

11.0 - 32.0

6 days to 3 months

11.5 - 28.3

4 to 12 months

11.9 - 25.6

1 to 6 years

12.3 - 22.8

7 to 11 years

12.5 - 21.5

12 to 20 years

12.6 - 21.0

Adults

12.0 - 22.0


High values than normal reference range are seen in hyperthyroidism and patients with acute thyroiditis.

Low values than normal reference range are seen in hypothyroidism, myxedema, cretinism, chronic thyroiditis, and occasionally, subacute thyroiditis.



Patient Concerns about Thyroxine - Free

Frequently Asked Questions about Thyroxine - Free

Q. What is Hyperthyroidism?
Hyperthyroidism is a condition in which the thyroid gland is overactive and there is an increased production of thyroid hormones by the thyroid gland. Causes of Hyperthyroidism include Graves’ disease, multinodular goiter, thyroid nodules, toxic adenoma, inflammation of the thyroid, eating too much iodine, and too much synthetic thyroid hormone. Diagnosis of this condition can help to relieve the symptoms and prevent long term complications.
Q. What are the symptoms of Hyperthyroidism?
Symptoms of Hyperthyroidism include: Rapid heartbeat (tachycardia) — commonly more than 100 beats/minute — irregular heartbeat (arrhythmia) or pounding of your heart (palpitations), sudden weight loss, nervousness, anxiety, irritability, tremor (usually a fine trembling in your hands and fingers), changes in menstrual patterns, increased sensitivity to heat, changes in bowel patterns (especially more frequent bowel movements), an enlarged thyroid gland (goiter) which may appear as a swelling at the base of your neck, increased appetite, sweating, fatigue, muscle weakness, sleep disturbances, skin thinning, fine and brittle hair
+ more

Provided By

NABL

NABH

ISO

Max Lab runs 11 NABL accredited, 24×7 operational laboratories in Delhi NCR, Punjab and Uttaranchal. Our labs are equipped with fully automated state-of-art technology and infrastructure to achieve the highest level of excellence and quality results. With over 500 highly trained staff and over 70 doctors who are trained in various sub-specialities at the best institutes in India and overseas, Max Lab boasts of having highly qualified haematologists, histopathologists, biochemists and microbiologists. We evaluate over 50, 00,000 samples every year with access to sample quantities not readily available to most institutions. This depth of experience directly benefits us in catering to the patient with complex or rare cases and in interpreting unusual results. At the core of our expertise is the ability to provide our patients with an extensive and ever-growing portfolio of cutting-edge and routine testing for a broad range of disease states. Our capability enables us to quickly and easily move from a sound diagnostic course of action to confident decision making for improved patient care. Max Healthcare, a leading name in the healthcare industry, brings its medical expertise and hospital-quality healthcare in the comfort of your home through Max@Home. With a special purpose to help people lead a life with independence and dignity, we deliver our services with compassion, excellence and reliability. To help you help you recover faster and lead a comfortable life, we provide nursing care attendants, physiotherapists and doctors for home visits. We also arrange for home sample collection and facilitate medical equipment on rent.

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