Do you have any queries?

or Call us now at 9982-782-555

back-arrow-image Search Health Packages, Tests & More

FT4-Free Thyroxine Serum Test

53+ booked in last 3 days

Free T4 Test Overview

T4 (thyroxine) circulates in body in a bound form with thyroxine-binding globulin and albumin.  Less than 0.3% of the total T4 is free fraction (FT4) and is the active form. Free T4 test measuring free T4 levels, more accurately reflect how the thyroid gland is functioning when checked with TSH.
Thyroid hormones are essential for growth and metabolism. Following are the symptoms of hyperthyroidism: weight loss, rapid heartbeat, tremors, sweating, anxiety, increased sensitivity to heat, etc. 
Whereas patients with hypothyroidism suffer from weight gain, fatigue, slow heart rate, increased sensitivity to cold, depression, dry and thin hair etc.

A thyroxine test or T4-Free Thyroxine Serum Test is used to diagnose thyroid conditions. The hormones produced by the thyroid gland help in controlling the way our body utilizes energy. Our thyroid is a tiny, butterfly-shaped gland. It is located at the base of our throat. The thyroid hormone also affects our weight, muscle strength, body temperature, heart health, and even our mood. When it comes to children, a thyroid disorder can affect their growth as well.

A T4-free thyroxine test measures the amount of thyroxine hormone in our blood. In case the level of T4 hormone in our blood is too little or too much, it is an indication that we may have thyroid disease.

T4 levels are measured using two different tests:

  • A free T4 test is used to measure the T4 levels directly in the blood. As per medical experts, this test provides more accurate information in comparison to the total T4 test.
  • The total T4 test is used to check the level of both free and found T4 together. This method is considered to be less accurate to check the working of our thyroid gland.

  The Free T4 test is done to:

  1. To diagnose thyroid disorders: The free T4 test is often used to evaluate thyroid function and to diagnose thyroid disorders such as hypothyroidism or hyperthyroidism.
  2. To monitor thyroid function: The free T4 test may be ordered to monitor thyroid function in people who are being treated for thyroid disorders.
  3. To assess the effectiveness of thyroid medication: If someone is taking thyroid medication, their free T4 levels may be checked to make sure the medication is working effectively.
  4. To assess fertility issues: The free T4 test may be ordered as part of an infertility workup, as thyroid disorders can affect fertility.
  5. To evaluate symptoms such as fatigue, weight gain, or weight loss: If someone is experiencing symptoms such as fatigue, weight gain, or weight loss, the free T4 test may be ordered to help diagnose or rule out a thyroid disorder as a possible cause.
  6. To monitor pregnancy: The free T4 test may be ordered during pregnancy to monitor thyroid function, as thyroid disorders can affect the health of the mother and the developing fetus.

Written by: Dr Vishal Wadhwa, M.D, D.N.B Microbiology, Medical Affairs

Reasons for Undergoing the FT4 Test  

Thyroid health plays a significant role in our overall well-being, influencing everything from energy levels to metabolism. The FT4 test, or free T4 test, is a vital diagnostic tool used to evaluate how well your thyroid is functioning. Understanding your thyroid hormone levels can provide important insights into your health and help identify any underlying issues. Here are several key reasons why you might need to undergo this FT4 blood test: 

  • Monitoring the effectiveness of thyroid replacement therapy 

  • Screening for thyroid problems in newborns and individuals with a family history of thyroid diseases 

  • Evaluating symptoms suggestive of thyroid dysfunction, such as weight changes, fatigue, and sensitivity to temperature 

List of Parameters Considered During the FT4 Test 

Thyroid health plays a crucial role in regulating various bodily functions, including metabolism, energy production, and growth. Understanding how well your thyroid is functioning can help identify potential health issues. One important tool for assessing thyroid function is the FT4 blood test, which focusses on one key parameter to provide valuable insights into your thyroid health: 

  • Free T4 (FT4): This measures the level of free thyroxine, the active form of the hormone that is not bound to proteins and is readily available for use by the body's tissues. The FT4 test result indicates the amount of thyroxine accessible to the body, providing a more accurate assessment than total T4 levels. 

Home Collection for FT4 Test Near You 

 At Metropolis Healthcare, we understand the importance of convenience and comfort when it comes to healthcare. That's why we offer a hassle-free home sample collection service for the FT4 blood test. Our trained phlebotomists will visit you at your doorstep to collect the required sample, ensuring your safety and comfort throughout the process. With our stringent standards of sample handling and testing accuracy, you can trust that your FT4 test results will be reliable and timely. We are committed to provide reliable, high-quality diagnostic services, delivered conveniently to your home 

Read More

FT4-Free Thyroxine Serum Test Price

Metropolis Healthcare is a leading diagnostics centre and pathology lab in India equipped with the latest state-of-the-art technologies that provides the FT4-Free Thyroxine Serum Test with a clear pricing structure. The FT4-Free Thyroxine Serum Test Price in Mumbai is ₹ 380. We are committed to deliver accurate and quality results from the best labs in India with complete transparency regarding test cost and turnaround time. No matter where you are, we strive to offer patients high-quality service that is affordable and accessible.

Frequently Asked Questions

Free T4 test is done along with 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

Free T4 test measures levels of FT4 hormone in blood

Free T4 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.

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

In most cases, no special preparation is required for this test. Make sure to inform your healthcare professional about any medicines or supplements you are taking as they can affect the results of the test.

There is little to no risk associated with a T4-Free Thyroxine test. You may experience slight pain or bruising at the injection site, but the symptoms disappear fast.

If you have taken a T4-Free Thyroxine test, the results will be reported as free T4. T4 levels lower than normal can indicate hypothyroidism, thyroiditis, or congenital hypothyroidism. On the other hand, higher than normal free T4 levels can be a sign of hyperthyroidism, thyroiditis, toxin thyroid nodule, toxic goitre, or a non-cancerous tumour in the pituitary gland.

Certain medications like phenobarbital can have an impact on your free T4 levels. Besides this, severe cases of chronic ailments such as cirrhosis of the liver or chronic renal failure can also affect your T4-Free Thyroxine test results.

The normal range for free T4 ranges between 0.9 and 2.3 nanograms per decilitre, or 12 to 30 picomoles per litre. However, the normal value ranges may differ slightly depending on the laboratory where you get your test done.

The normal range for free T4 classified according to age are as follows:

o   Children/adolescents: 0.8-2 ng/dL

o   Adults: 0.7-1.8 ng/dL

o   Pregnant women: 0.5-1 ng/dL

Normal TSH with normal T4 indicates normal thyroid function. However, high TSH along with a normal T4 means we are at a higher risk of developing underactive thyroid. On the contrary, low TSH levels with high T4 levels mean that our thyroid gland is overactive.

Your healthcare provider may recommend you to get a T4-Free Thyroxine serum test if you show any signs of thyroid disorder, such as:

 

  • Symptoms of underactive thyroid
  • Symptoms of overactive thyroid
  • Abnormal findings in other types of thyroid tests, like T3 or TSH
  • Hypopituitarism – a condition where the pituitary gland fails to produce enough hormones
  • Nodule or Lump in the thyroid gland
  • An irregular or enlarged thyroid gland
  • Problems getting pregnant

Thyroid disorder is a hereditary condition. Therefore, your doctor may prescribe you a T4 test in case anyone in your family has a thyroid disorder. You may also require a T4 test if you show any symptoms of too little or too much thyroid hormone.

 

Common symptoms of hypothyroidism include:

 

  • Weight gain
  • Fatigue
  • Dry, thinning hair
  • Dry skin
  • Over-sensitivity to cold temperatures
  • Heavy menstrual periods or fertility issues
  • Depression
  • Slow heart rate

 

Symptoms of hyperthyroidism include:

  • Nervousness, irritability, and anxiety
  • Weight loss
  • Muscle weakness
  • Shaky hands
  • Over sensitivity of heat
  • Arrhythmia
  • Goiter
  • Frequent bowel movements
  • Fatigue and trouble sleeping

o   Free thyroxine

o   Free T4

o   Thyroxine screen

The FT4 test is a blood test that assesses the amount of free thyroxine (T4) in the bloodstream. This is the active form of the hormone that is not bound to proteins and is ready for immediate use by the body's tissues.

The FT4 test is essential for diagnosing and monitoring thyroid disorders such as hypothyroidism and hyperthyroidism. It provides accurate information about the active form of thyroxine available to the body, crucial for managing thyroid health and metabolic function.

T3 stands for triiodothyronine, while T4 represents thyroxine. These are the two main hormones produced by the thyroid gland.

TSH stimulates the thyroid gland to produce T4, which is then converted into the more active form, T3. The levels of T3 and T4 in the blood provide feedback to the pituitary gland to adjust TSH production, maintaining a balance in thyroid hormone levels.

Yes, the Free T4 Test can be taken during pregnancy. However, it is important to inform your healthcare provider about the pregnancy, as it can affect the test results and their interpretation. 

A low FT4 level may indicate hypothyroidism, which can cause symptoms such as weight gain, fatigue, dry skin, sensitivity to cold, and other metabolic disturbances.

If your FT4 levels are high, indicating hyperthyroidism, treatment may involve medications to reduce thyroid hormone production, radioactive iodine, or surgical removal of part or all of the thyroid gland, depending on the underlying cause and severity.

The FT4 test can be performed at any age, including newborns, to screen for congenital hypothyroidism and in adults to diagnose and monitor thyroid disorders.

The benefits of the FT4 blood test include accurate diagnosis and monitoring of thyroid disorders, differentiating between primary and secondary thyroid issues, and guiding treatment decisions to ensure optimal thyroid function.

No, fasting is generally not required before taking the FT4 test. However, inform your healthcare provider about any medications or supplements you are taking, as some may affect the test results.

Metropolis Healthcare provides a hassle-free home sample collection service for the FT4 test. A trained phlebotomist will visit your home to collect the sample, ensuring both comfort and safety. With strict adherence to sample handling standards, you can rely on Metropolis for accurate and dependable FT4 test results.

Typically, results for FT4 test are available after 6 hours, depending on the day/time the sample was collected and processed. 

full medical check up

Ratings & Reviews (0)

No reviews available

Why Metropolis?

Metropolis has a team of 200 senior pathologists and over 2000 technicians delivering diagnostic solutions in the areas of routine, semi specialty and super specialty domains like Oncology, Neurology, Gynaecology, Nephrology and many more.

We offer a comprehensive range of 4000+ clinical laboratory tests and profiles, which are used for prediction, early detection, diagnostic screening, confirmation and/or monitoring of the disease.

lab image
170+ Advanced Labs
lab image
Trusted by Leading Doctors & Hospitals
lab images
Over 2000+ Scientific Officers
reports image
Proficiency Testing for Accurate Reports

Our Blog

Take a look at some of the related content from our blog

Latest Blogs & News

View More
View all