Overview
Free thyroxine (FT4) comprises a small fraction of total thyroxine. FT4 is available to the tissues and is, therefore, the metabolically active fraction.Elevations in FT4 cause hyperthyroidism, while decreases cause hypothyroidism. Pediatric 0-5 days: 0.9-2.5 ng/dL, 6 days-2 months: 0.9-2.2 ng/dL, 3-11 months: 0.9-2.0 ng/dL, 1-5 years: 1.0-1.8 ng/dL, 6-10 years: 1.0-1.7 ng/dL, 11-19 years: 1.0-1.6 ng/dL Adult (> or =20 years): 0.9-1.7 ng/dL
What is Free T4 (free Thyroxine) ?
Normally, Thyroxine (T4) is attached to proteins like albumin and thyroxine-binding globulin (TBG) while circulating in the bloodstream. The hormone's physiologically active form, known as Free T4 (FT4), is just a small percentage of the total T4 that is unbound. In order to control the body's metabolism and energy generation, a free T4 test is essential. Both free and total T4 levels are typically high in hyperthyroidism; however, the Free T4 Test offers a more precise assessment of thyroid function, particularly in circumstances where protein-binding is disrupted, like pregnancy or specific medical disorders. While lower levels may signify hypothyroidism, elevated FT4 levels are often linked to hyperthyroidism or excessive thyroid hormone replacement medication. In order to assess thyroid function and provide guidance, the Free T4 Test is crucial.
What is the Cost of Free T4 (free Thyroxine)
The price of a Free T4 Test is Rs. 200. However, cost of the test may fluctuate depending on following factors:
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Other tests advised along with this thyroid test
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Offers or discounts
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Empanelment of the patient
What is the Purpose of the Free T4 (free Thyroxine) ?
Free T4 Test is advised to for following analysis:
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Follow up on an abnormal TSH test result
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Diagnose hyperthyroidism, a condition involving an overactive thyroid gland
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Monitor T4 levels if you are on thyroid replacement therapy
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Diagnose hypothyroidism, a condition in which the thyroid gland is underactive
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Screen for an underactive thyroid gland in newborn babies
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Evaluate other disorders, such as goiters, thyroid nodules, and problems with the pituitary or hypothalamus gland
When is the Free T4 (free Thyroxine) Recommended ?
If you have following symptoms, then Free T4 Test is advised:
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Fatigue
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Feeling cold
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Weight gain
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Painful joints and muscles
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Thin and/or dry hair
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Dry skin
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Slow heart rate
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Depression
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Constipation
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Irregular menstrual periods
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Fertility problems
Preparation for Free T4 (free Thyroxine)
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Unless otherwise directed by your doctor, there is no need for you to make any special preparations before the Free T4 Test.
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Other blood tests can be carried out in addition to a Free T4 Test. If your doctor advises you to have multiple tests at once, they may ask you to fast for a specific period of time prior to a blood test.
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Drink adequate water before sample collection.
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Avoid vigorous physical activity before the sample collection.
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Follow the preparatory instructions as guided by your doctor.