Free Thyroxine (FT4) Test

The human body is an ever-growing organism and to grow, it needs energy. The energy is extracted or produced from enzymes that bond with a hormone produced by the thyroid gland called T4.

An excess of anything is always harmful to the human body. Similarly, with T4, an abnormally high amount of Free T4 can cause severe health issues. Elevated Free T4 levels may also suggest possibilities of Thyroiditis or Toxic Multinodular Goitre.

The Free T4 test, formally known as Free Thyroxine Test, is recommended by doctors to accurately measure the amount of T4 hormones not being bound with blood tissues. The laboratory test is essential for the official diagnosis of Thyroiditis and measures Free T4 (FT4) or Free T4 Index (FTI).

A regular Free T4 blood test can be recommended based on some studies proving that ignored, elevated measures of Free T4 can mean an increased risk of solid cancers such as lung cancer, breast cancer and prostate cancer.

Hypothyroidism is a disease wherein the thyroid gland releases excess T4 hormones, which slows down metabolism, causing problems like weight gain, uneasiness and low tolerance to cold temperatures.

You can also make Free T4 Tests a part of your health check-up if you start to feel a sudden weight change, fatigue or anxiety. Also, check for other symptoms like dry skin, hair loss and hand tremors. If the Free T4 Test results are abnormal, consult your doctor.

Thyroid-related problems are rising in India, where 1 in every 10 Indians have hyperthyroidism. The cause can vary from a deficiency of iodine to contaminated water and environmental factors.

While the common belief is that obesity and heart problems are inherited from predecessors, the fact is the typical Indian diet and a lack of exercise can be the causative factors here. With proper diet and regular exercise, thyroid disorders can be avoided to a major extent.

Thyroiditis, Goitre, Autoimmune disorders

There is a varied list of reasons your consulting doctor may prescribe a Free T4 test, but the most common scenario is a follow-up to an abnormal TSH test. Free T4 tests are preferred over T4 tests when the doctor wants to know the accurate measures of Free T4 available in the blood.

The diseases/conditions for which a Free T4 test can be prescribed are:

• Goitre
• PCOS (and other menstrual irregularities)
• During pregnancy
• Obesity
• Hereditary history of thyroid disorders
• Autoimmune disorders
• Diabetes
• Graves’ Disease

Symptoms related to thyroid disorders can be a major concern for doctors as well. 42 million adults in India are suffering from hypothyroidism. The symptoms of hypothyroidism are:

• Fatigue
• Depression
• Anxiety
• Sudden weight changes
• Dry, puffy face
• Dry, baggy eyes
• Insomnia
• Irritability
• Mood swings
• Loose/frequent bowel movements
• Rapid, irregular heartbeat

Consulting your doctor before getting tested is recommended. The free T4 test after every 6 months is advisable as a precaution against severe diseases.

Depending on the specific symptoms you are presenting with, you can consult a doctor and based on their recommendation/suggestion, you can take the Free T4 test. If the results of the Free T4 test are normal, it is advisable to retest every 6 months to measure your Free T4 levels.

You can also get your TSH or Thyroid Stimulating Hormone levels checked using the same blood sample. The TSH and Free T4 test results may vary as they are two different tests.

Before the Test

Generally, no special test preparation is required before an Free T4 test. However, if this test is done in conjunction with another test, your physician may ask you to avoid certain food items. In order to get the most accurate results, it is necessary to consult a medical professional before taking the test.

During the Test

A phlebotomist will draw blood from a vein in your arm to collect a sample. Your experience will be something like this:

• The area where the needle will be inserted is cleaned with antiseptic lotion.
• A tourniquet band is tied around the arm to dilate the veins.
• A new syringe needle will be inserted into the vein to draw blood. This procedure may take a few seconds, during which you may feel a slight pain of needle pricking.
• Your blood sample will be stored in a small vial or test tube with your test details.

After the Test

Once the blood is collected:

• A sticking plaster is applied to the needle insertion site to prevent bleeding.
• There may be a slight soreness or lightheadedness in some cases, nothing to worry about. You may be asked to sit for a few minutes.
• Contact your doctor if there is bleeding, pain or rashes at the puncture site.

The sole reason for a prescription of the Free T4 test is to accurately measure the excess of T4 hormone present in your system.

You might be recommended this test after consulting with your doctor about any sudden changes in your weight and increased anxiety and fatigue. A puffy face and dry face are also indicators that you need to see a doctor. Also, check for eye-related issues like dryness. Obesity and joint pain are also triggers that signify a need for Free T4 test results.

This test is not the final diagnosis of hyperthyroidism but a mere part of the diagnosis. Pregnant women and women over 60 years of age often experience higher levels of the Free T4 hormones than the normal range of Free T4 test results.

There is a possibility of elevated Free T4 levels in pregnant women and women over 60 years of age.
The ranges may differ between the genders, but this is considered the formal range of the Free T4 test results.

The normal values and reference ranges of the test may vary from lab to lab. Please refer to the ranges mentioned in the report and consult a doctor to understand the interpretation of lab reports.

It is important to consider the results of the TSH test and the T3 test together to fully understand the results of the Free T4 Test. The results from different labs may vary, as the test process or laboratory may be different. Speak to the result provider to get complete clarity on your test results.

Conditions like pregnancy, liver problems and oestrogen levels may also have an effect on the results.
An excess in the Free T4 hormones can be an indicator of the following diseases:

• Graves’ Disease
• Diabetes
• Thyroiditis
• Toxic Goitre or Toxic Thyroid Nodules
• Rarely, a tumour near the ovaries

To properly understand what the test results highlight, speak to your consulting doctor and learn the next steps. Doctors highly recommend including the TSH tests in routine check-ups.
Note: If the results come in normal, you are advised to retake the test after 6 months as a precautionary measure.