The FTI blood test is a measurement of a person’s free thyroxine index. There are a wide variety of thyroid uptake tests that can be ordered. The FTI blood test uses a mathematical computation to estimate results from T3 and T4 uptake tests. The information lets doctors estimate how much free hormones produced by the thyroid are available in the blood for the body to use.
This test is not commonly ordered because the results are more of an estimation than an accurate result. Because the test results are not affected by altered estrogen levels, however, women who are pregnant will often have this test ordered to obtain results.
Why Is the FTI Blood Test Ordered?
The CDC in the United States estimates that up to 30 million people could be suffering from some form of thyroid dysfunction right now. It is especially prevalent in women and seniors. People who have sudden weigh gains or losses, have frequent mood changes, or have unexplained fatigue that is prolonged will benefit from having this test ordered. Based on the results, the thyroid functioning will be determined to be overactive, underactive, or normal.
The thyroid makes two essential hormones that stimulate the gland and cause it to add or decrease levels so that energy expenditure can be achieved. It has an integral role in the systematic functioning of the body so that calories can be burned, foods digested and not stored as fat, and even regulate heart functioning.
This is combined with a measurement that is called TSH – thyroid stimulating hormone. When the FTI blood test is ordered, the TSH test is often ordered with it to get a complete picture of what the thyroid is doing.
What Do the FTI Blood Test Results Mean?
Most people are going to have their test results come back as normal. There are two combinations that may also occur. There can be high levels of TSH and low levels of hormones or this may be reversed.
If you have high TSH levels, but low levels of thyroid hormones on your FTI results:
This means that the thyroid is trying to function normally, but it is unable to maintain hormone levels within the blood for some reason. This generally indicates a thyroid is underactive and this can lead to depression, constipation, pale skin that is dry, facial swelling, joint pain, and muscle weakness. People with an underactive thyroid are particularly sensitive to the cold.
If you have low TSH levels, but high levels of thyroid hormones on your FTI results:
This is an indication that the thyroid is being over-stimulated and is being overactive. Shaking hands, heat intolerance, a rapid heartbeat, trouble sleeping, muscle weakness, and swelling in the neck can all be symptoms of this. Hyperactivity and weight loss that is unexplained, along with excessive sweating, are also common symptoms.
According to information from the American Thyroid Association, every adult should be tested for thyroid functioning starting at the age of 35. For those who receive normal FTI blood test results, a 5 year follow-up is recommended. Those who have a family history of thyroid dysfunction will want to get tested earlier.
Because many of the symptoms can be similar to other diseases, an imbalanced thyroid is not always the first thought that enters a doctor’s mind. Patients may need to specifically request that this blood test be ordered to make sure that the full picture of their health is examined.
How Are Abnormal FTI Blood Test Results Treated?
People who are under high amounts of stress and consume high amounts of caffeine may be negatively impacting their thyroid function. Lifestyle habits will be examined first. Finding ways to relax while reducing stimulants can help to improve thyroid functioning over time. People over 50 may have hormonal changes occurring which may also affect the gland from functioning properly. Adrenal and cortisol testing may be ordered to determine an underlying cause.
Otherwise the treatment plan a doctor will develop with each patient is designed to restore the thyroid gland to normal functioning. The most common way to do this is through hormone replacement therapy. It often helps people return to a normal way of life, improve their rest, and have their mood return back to normal fairly quickly.
Individual results may vary and indicate different health outcomes.
Only a medical provider can specifically tell a patient what their test results mean. If you have questions about your FTI blood test results, then be sure to schedule an appointment with a your provider immediately.