May 11, 2021
Thyroid issues: testing (like TSH, T4, T3, free T3, Free T4, Reverse T3) – Dr. Jason Jones Elizabeth City NC, Chiropractor
In this month of MAY, being Women’s Health Month, we are going to discuss one of the common conditions affecting women - thyroid issues. These health conditions can come in form of hypothyroidism, hyperthyroidism, or autoimmune thyroid diseases such as Hashimoto’s thyroiditis or Grave’s disease.
We are also going to discuss blood tests for thyroid function – like TSH, total T4, free T4, Free T3, rT3, and others. These tests are parts of important for diagnosing and treating these thyroid issues.
Usually, a combination of tests is needed to establish the full nature of your thyroid health, but sometimes, a single test is enough to draw some conclusion. The values of the thyroid tests help doctors determine the kind of thyroid issue a person is having.
What is the thyroid gland?
The thyroid gland is a butterfly-shaped endocrine gland that is located at the front of your neck. The job of this gland is to make thyroid hormones, which help the body use energy and keep the heart, brain, muscles, and other organs working optimally.
The thyroid hormone is secreted into the bloodstream and transported to every tissue in the body. The majority of this hormone is thyroxine, also called T4 (containing four iodine atoms).
This T4 is often converted to triiodothyronine (T3), through the removal of a single iodine atom. This effect takes place mostly in the liver and in some tissues where the T3 acts, including the brain.
Another gland called the pituitary gland secretes the thyroid-stimulating hormone (TSH) which controls the amount of T4 produced by the thyroid gland. The amount of TSH produced is dependent on the amount of T4 the pituitary sees.
More TSH is often produced if the pituitary sees very little T4. But once the T4 goes above a certain level, the production of TSH is automatically shut off.
You can liken the work of the thyroid and pituitary gland to the action of a heater and thermostat. When the heater is cold, the thermostat reads and turns on the heater, and when the heat rises to a particular level, the thermostat senses this and turns off the heater.
Having a sufficient amount of the T4 AND T3 hormones is important to maintain the work of the thyroid gland in the body.
An imbalance of the thyroid hormones can lead to various health issues, hence various testing methods are used to determine the level of these hormones in the body
Testing methods
Blood tests are usually taken to measure the amount of thyroid hormone in the body. Some of the tests commonly used to evaluate thyroid function include:
TSH tests
This is the first test to check thyroid function. It is conducted to measure the TSH level in a blood sample. A high TSH level indicates that the thyroid gland is not secreting enough hormone (primary hypothyroidism).
A low TSH level usually arises from an abnormality in the pituitary gland, which disrupts the ability to stimulate the thyroid (hyperthyroidism).
Usually, a normal TSH value indicates that the thyroid is working properly.
T4 tests
T4 is the main thyroid hormone circulating in the blood. A total T4 gives a measure of the free and bound hormone, and this value can change when the binding proteins differ.
A free T4 measures the T4 hormones that are not bound and can enter and affect the body tissues.
Tests that measure free T4 -either free T4 (FT4) or free T4 index (FT1) - are more accurate in reflecting the thyroid function when checked with a TSH.
A Low FT4 OR FTI and an elevated TSH indicate primary hypothyroidism due to disease in the thyroid gland. A low FT4 or FTI and a low TSH shows an individual has hypothyroidism due to an issue with the pituitary gland. An elevated FT4 or FTI and a low TSH are found in people suffering from hyperthyroidism.
T3 tests
T3 tests are usually conducted to diagnose and determine the severity of hyperthyroidism. An elevated amount of this hormone is seen in hyperthyroid patients.
Some individuals having a low TSH shows an elevated amount of the T3 alone with the FT4 or FTI remaining in the normal range.
A T3 test is rarely needed in people with hypothyroidism as it is the last test to become abnormal. People with a severe case of hypothyroidism can have a high TSH and low FT4 and FTI but maintain the normal T3 value.
A free T3 measurement is often not reliable, so it is not helpful.
Reverse T3
Reverse T3 is structurally similar to T3 but the iodine atoms are located differently, which makes it inactive.
In healthy people, measurement of reverse T3 is useful as it helps determine that if there is a high rT3 which can lead to blocking the ability of T3 to be utilized.
If you’re concerned about your energy level, you can exercise more, eat a healthy whole food diet, reduce stress, and sleep well it would be a good idea to get your thyroid tested.
You can consult Dr. Jason Jones at our Chiropractic office in Elizabeth City, NC, to learn more about thyroid issues and natural ways to stay healthy.